EC 1255 - PDF document

EC 1255 ¥ Revised May 2003 $2.50 FOREST PROTECTION Gopher habits and habitat..............1Control program...........................2pest......................Assessing the need for treatment...techniques...........Applying controls..........................7plantations.............Summary....................................8Sources of supply.........................8For further information..................8 sion wildlife specialist, and KimAsman, formerly College of Gopher habits and habitatThree species of pocket gopher can damage conifer seedlings. The twosmaller ones, the northern pocket gopher and the Mazama pocket gopher,are 5 to 9 inches long and brown with some white beneath the chin andbelly. The northern gopher is found east of the Cascade Mountains inOregon and Washington and in Idaho; the Mazama lives in Oregon andWashington west of the Cascades.The Camas pocket gopher is similar looking, but larger (10 to 12 inches)than the two others. It lives in Oregon north of Eugene in the WillametteValley, including the foothills of the Coast and Cascade ranges.All are easily identified by their fur-lined external cheek pouches andlarge orange front teeth, which are used to clip roots and dig tunnels. Theyhave powerful front legs and large, curved claws for burrowing (Figure 1). Figure 1.ÑTypical Oregon pocket gopher.damage conifer seed-lings on thousands ofacres in Washington,Idaho, and Oregonannually. Theyinvade clearcuts andclip (cut off) roots or 2 THE WOODLAND WORKBOOK They spend most of theirlives in their extensiveburrow systems, whichusually are 4 to 12 inchesunderground and cancontain over 500 feet oftunnels.Gophers feed mostlyabove ground on grassesand weeds close to theburrow opening. They alsofeed underground on theroots of forbs, shrubs, andtrees. Most girdling ofseedlings and saplings is ineastern Oregon and Wash-Mating is in early spring; four to eightyoung are born 3 weeks later. In earlysummer, the young are driven from thefemales burrow to establish their ownsystems. Gophers breed at 1 year of age,usually have only one litter a year, and havea life expectancy of 1 to 3 years.Gopher density varies with habitat con-ditions, ranging from four to twenty peracre. In areas with abundant food, burrowsystems are shorter and gopher densities arehigher. Control programIdentifying the pestIdentification is based on characteristicsof damage and burrow systems. Physicalcharacteristics of gopher damage areunique. Gophers clip roots and rootlets,leaving only the main stem of the seedling(Figure 3). Needles of gopher-damagedseedlings wilt and turn brown, and theseedling can be pulled out of the groundeasily.Gophers may pull entire seedlings belowground. They girdle seedlings and saplings,especially during winter. Girdled seedlings/saplings look sculptedŽ(Figure 4). Individualtoothmarks are 1‡ inchwide. A gopher burrowingthrough snow can girdleconifer stems as high assnow depth, which may be7 feet or more above ground.Voles, like pocketgophers, damage seedlingsby girdling, but their teethare so small that gnawedbark looks fuzzy. Voletoothmarks are about1‡ inch wide.Porcupines occasionallygirdle conifers at groundlevel, but their toothmarks(1‡8 inch wide) are twice aslarge as those of gophers.Figure 2.ÑEarthen ÒcastsÓleft above ground by gopherstunnelling through snow.Figure 3.ÑTypical gopher clipping damageto a seedlingÔs root system.Figure 4.ÑA ÒsculptedÓ(girdled) seedling, which istypical gopher damage.ington during winter, when the gophersburrow system extends above ground intothe snow.The soil that gophers push out into thesesnow tunnels forms the curious casts orworm tracks left on the surface of theground after snowmelt (Figure 2).Gophers inhabit small forest openingswhere they find their preferred foods. Suchopenings are natural meadows or have beencreated by clearcut logging.Within months, gophers invade regenera-tion sites from adjacent clearcuts or mead-ows. Gophers can travel more than 300 feetabove ground and 2,500 feet under snowcover when moving from established forestopenings to new clearcuts.Gophers are solitary exceptduring the breeding season. Normal FOREST PROTECTION 3Gophers system of mounds, earth plugs,and winter casts is distinctive. The moundis horseshoe- or fan-shape (Figure 5).and spread it around the opening (about2 inches wide) at one edge.Mole mounds look like those of pocketgophers, but they are volcano- rather thanfan-shape and the opening is in the centerof the mound.The mound pattern of pocket gophers isdifferent from that of moles. Moles push upa series of single mounds in nearly straightlines, but gophers cluster mounds in irregu-lar groupings (Figure 6).Voles burrow but do not mound dirt atthe tunnel entrance. Their openings (aboutthe size of a fifty-cent piece) are smallerthan those of gophers and are intercon-nected by aboveground trails.Assessing the need for treatmentthe need to control gopherdamage should be part of your harvest andreforestation planning. The standardmethod is to measure gopher activity by themound survey, which is an index of gophernumbers.To assess gopher numbers, check plots ofone-tenth acre (square areas 20 feet on aside, or circles with 24-foot diameters) forpresence of gopher mounds. One one-tenth-acre plot per acre of regeneration site isrequired to accurately assess the need forgopher control. Usually, plots are laid outon lines (transects) across regeneration sitesso that adjacent plots are at least 150 feetapart (Figure 7, page 4).Begin your control measures on sites upto 2 years old if 25 percent or more of theplots contain active mounds, and on sites3 to 5 years old if 40 percent or more of theplots contain active mounds.Damage control techniquesYoull achieve maximum effectivenessof most control techniques if you canemploy them before youplant seedlings.Most forest managers are willing to applycontrol techniques before planting only ifdamage is very likely„thats why itsimportant to conduct your mound survey.Where its possible, combine severalcontrol techniques. This will give betterresults than if you use just one.Fumigating Fumigants (cartridges andpellets) release poison gases (carbonmonoxide and sulfur dioxide) into thegophers burrow system. They are mosteffective when the soil is damp„when yousqueeze a handful, it forms a ball ratherthan crumbling.Fumigants wont work when the soil isdry because the gas leaks. Fumigants workbest in spring or fall when soil is moist andgophers are most active (their mounds areeasier to spot then, too).Open the burrow tunnel down to themain runway with a shovel or trowel. Igniteand place a gas cartridge (or two or threepellets) 6 to 10 inches down the openedrunway. Stuff newspaper in the burrowentrance and cover with several shovelfulsof soil to block escape of poison gas.If the gas doesnt kill the gopher, thegopher usually clears its runway of residualgas by digging many exit holes near theburrow entrance. Then, use trapping orAnother way to gas gophers is to use ahand-held propaneweed burner(Figure 8, page 4)and dusting sulfur.Figure 5.ÑA typical gopher mound.Figure 6.ÑMole mounds are easily distinguished from pocketgopher mounds. MolePocket gopher 4 THE WOODLAND WORKBOOKOpen the burrow down to the main runwayand place about 1 cup of dusting sulfur inthe burrow entrance. Turn the gas on fullforce and light it. The flaming propane willignite the sulfur.The sulfur burns bests when you hold thetorch about 6 inches away. Thick, whitesmoke will begin to seep from other burrowentrances; cover these with shovelfuls ofsoil. The sulfur burns up in about 30 sec-onds. Cover the burrow entrance with soilwhen youve finished burning the sulfur.Fumigating is time consuming, so use itonly when you need to treat areas less than5 acres. Fumigating poses minimal risk tonontarget animals because its used only inactive gopher burrow systems„andgophers dont tolerate other animals in theirburrows. Fumigating, like other lethalcontrol methods, usually must be repeatedto get the gophersyou missed with thefirst application.To determinewhether you need totreat again, flatten allyou fumigate. Returnin a week and treatall burrow systemswhere the moundshave been rebuilt.They are a sign that you didnteliminate all gophers with thefirst treatment.Gophers from adjacent areaswill invade rapidly and usetunnel systems of gophers killedin control programs. To preventreinfestation, fumigate gopherburrows in a buffer area 300 feetwide outside your regenerationsite.is effective buttime consuming, so trap smallareas (less than 5 acres) or inplaces where poison baits cantbe used. Follow up fumigatingor poison baiting with trappingto remove gophers resistant togas or baits.Use Victor or Macabee traps.Locate the main runway of the burrowsystem by pushing a probe (an iron rod,Figure 9) repeatedly in the ground in thearea between two adjacent fresh mounds.Youll know when you hit the runwaybecause the probe suddenly will sink 2 to4 inches in the ground. Dig an openingdown into the runway and place two trapsas shown in Figure 10.Anchor the traps with wire and flag themto make relocation easy and to preventscavengers from dragging away traps withdead gophers. Leave the opening partiallyopen; this will attract the gopher to the traparea. The gopher will be caught coming ineither direction as it attempts to plug theopen runway.You may put traps in lateral runways atthe mouths of opened burrows, but yoursuccess will be higher when you place themFigure 8.ÑHand-held propane Ògopher gasser.ÓFigure 7.ÑLayout of plots on transect lines for assessing need to controlgopher damage. Individual plotTransect lineTransect line Propane gas(5-gallon L-P tank)10-foot flexibleL-P gas hose18-inch OD connector pipeBarrel FOREST PROTECTION 5in the main runway.Trap in fall and springwhen the soil is softerand easier to dig andgophers are creatingnew mounds moreactively. Trap a bufferzone 300 feet wideoutside the regenera-tion site if possible.Trapping, likefumigating, doesnteliminate all pocket gophers, so youll needto return to eliminate surviving gophers.Just as you did for fumigating, flatten allmounds the first time you set the traps andretrap all burrow systems where themounds are rebuilt a week later.Poison baiting Poison baits areextremely effective for controlling gopherdamage. Grain baits containing 0.3 to0.5 percent strychnine alkaloid are availableat many farm and garden supply stores.Baiting is hazardous not only to smallmammals (such as voles, chipmunks, andgolden-mantled ground squirrels) that eatbaits in gopher burrows but also to hawks,owls, and mammalian predators and scav-engers (weasels, skunks, foxes, coyotes,and bobcats) that feed on gophers.Hazard to predators and scavengers islow because most poisoned gophers will diein the burrow system and be unavailable tothese animals. If seed baits are spilledabove ground and not cleaned up, they posea serious hazard to seed-eating birds, whichare highly susceptible to strychnine.Poison baiting is most effective in earlyspring, when natural gopher foods are inlow supply.Locate main runways with a probe.Rotate the probe in a circle several times toenlarge the hole, then remove the probe anddrop 1 teaspoon of bait into the tunnel.Close the hole with a dirt clod.If the opening is left open, the gopherwill plug the runway at that point, coveringthe bait. Never scatter bait around theburrow entrance„birds will be poisoned ifyou do. Make three to five bait placementsper cluster of fresh mounds.You can bait with a probe-bait dispenser(Figure 11, page 6). This device cutstreatment time in half because you probeand place bait in one step. Be sure to useonly grain baits because pelleted baits will Figure 10.ÑCorrect placement of gopher traps.jam in probe-bait dispensers.Locate themain runwayusing thedispenser as aprobe. Push abutton or leveron the dispen-ser to release ameasuredamount of baitinto the tunnel,then pull thedispenser fromthe ground.Cover theresulting smallhole with arock or clod.Probe-baitFigure 9.ÑProbe used to locate gopher tunnel system. FootÚ4" Gas pipe14"Round endsolid iron5" Stake with flaggingMain runway 6 THE WOODLAND WORKBOOK dispensers work poorly insummer in soils with ahigh clay content becausethe probe cant penetratethese soils when dry.For treating fairly flatareas of more than10 acres, you can bait withthe burrow builder(Figure 12). You pull aburrow builder behind atractor to create artificialgopher burrows. Burrowbuilders automaticallydispense poison baits intothe artificial tunnels.Gophers investigate theseartificial burrows andencounter and eat thebaits. If strychnine alka-loid is labeled for use witha burrow builder, then thatformulation is a restricted-use pesticide, and acertified applicatorslicense is required to use it.Burrow builders disperse poison baits tentimes faster than hand baiting, but their useis restricted to areas with slopes of less than20 percent and soil relatively free of rocks,roots, and debris. The surface of the groundmust be relatively free of slash.Burrow builders work well only withseed baits (pelleted baits jam in the device),and they require a tractor with a minimumof 25 horsepower.Like the probe-bait dispenser, the burrowbuilder is most effective when soil is moist,in late fall and early spring. (For moreinformation on using the burrow builder,see OSU Extension publication EC 1117,retreatment. Use the open-burrow surveyŽto measure reduction in gopher activityresulting from control methods.Establish 40 or more square samplingplots, 20 feet on a side and at least 100 feetapart, before applying poison baits. Openthe entrances of all active gopher burrowswithin each plot. Examine the plots 24 to48 hours later to determine gopher activityplugged) and to record the number of plotswith gopher activity.Repeat the survey 1 to 2 weeks after youapply poison baits. To see how much youreduced pretreatment activity, divide thetreatment by the number before treatment,then multiply by 100. Rebait sites withmore than 20 percent gopher activity.Manipulating habitat Gophers responddirectly to changes in availability of pre-ferred foods. When you eliminate grassesand forbs by applying herbicides, thenumbers of gophers and the damage toconifer seedlings drop. Timing is importantif you plan to use vegetation managementto control gopher damage.Plant your conifer seedlings well afteryouremove grasses and forbs (even as longas 1 year). If you plant too soon, thegophers will find only seedlings to eat aftertheir preferred foods are eliminated„andtheyll devour every seedling.Habitat manipulation only reducesgopher numbers and damage, so youll needto follow up with lethal controls to removeremaining gophers.Postharvest treatments before plantingshould create a favorable site for seedlingsbut not for gophers. If you use broadcastBaitrelease leverHandleProbe endFigure 12.ÑBurrow building.ControllingPocket GopherDamage toAgriculturalWhen you baitsites larger than20 acres, its tootime consumingto flatten andcheck eachmound afterbaiting to deter-mine the need forBait canisterFrameCoulterBait tubeTorpedoPressure wheelsBait meteringdevice Figure 11.ÑProbe-baitdispenser. FOREST PROTECTION 7 €Wea€Re€Be Applying controlsChristmas tree plantationsMany plantation sites were grass fieldsbefore being planted to conifers. Such sitesoften provide excellent food and cover forgophers. Managing grass and forb vegeta-tion is extremely important: the fewer theforbs and grasses, the fewer gophers therewill be.However, dont plant such sites until atleast 6 to 12 months after you remove grassand forbs and have eliminated survivinggophers by trapping and/or handbaiting.You can discourage gopher entry into thesite by maintaining a buffer zone free ofof plantations. However, this may not bepractical or feasible.After youve controlled grass and forbvegetation, periodic site inspections willreveal anygopherinvasion.Deal withthesepromptly bytrapping,baiting, orboth. If aChristmastree planta-tion isheavilyinfested,baits with aburrowbuilder (seepage 6) isthe quickest and cheapest solution.Forest plantationsManaging vegetation is a key to keepinggopher damage to a minimum. If possible,tion sites through burning and/or herbicideuse. If you can manage the vegetation inthis manner, a yearly inspection of regen-eration sites will reveal any small-scalegopher invasions. You can treat thesepromptly and efficiently with hand baiting,trapping, or both.For regeneration sites with establishedpopulations, the traditional control methodis to contract probe-baiting out to a profes-sional consulting service (usually twoapplications, with a follow-up to establisheffectiveness). If you can use the burrowbuilder, youll greatly speed up the baitingprocess, and you may be able to bait abuffer zone.In areas with high winter girdling lossand deer and elk damage, you might con-sider using Vexar tubing. Plant the tubingaround the roots, extending 8 to 10 inchesbelow ground and extending 1 foot or moreground, to provide dual protection againstbrowsing by deer and elk and against wintergirdling by pocket gophers.Vexar tubing tends to collapse from theweight of snow, and snow movement tendsanswer is to fix the tubes in place with two 8 THE WOODLAND WORKBOOKbamboo sticks threaded through the Vexarmesh. Once the sites are free of snow in thespring, inspect the tubes for distortions ormovement and restore them to the properconfiguration to protect the seedlings. 1.Managing grass and forb vegetation to2.Selecting and applying appropriate3.Assessing effectiveness of your control Sources of supplyHere are some major manufacturers ofprobe-baiting dispensers and burrowbuilders. This list isnt exhaustive, and itsnot an endorsement by the Oregon StateExtension office that serves your county fora list of nearby distributors.Probe-baiting dispensersRCO, Inc.P.O. Box 191Harrisburg, OR 97446Tel. 541-995-7799Burrow buildersRCO, Inc.(address and phone as above)All American Ag724 Woodard CanyonTouche, WA 99360Tel. 509-394-2910 For further informationdeCalesta, D.S. Controlling Pocket GopherDamage to Agricultural Crops, EC 1117.1999. Corvallis: Oregon State UniversityExtension Service.Order from:Publication OrdersExtension & Station CommunicationsOregon State University422 Kerr AdministrationCorvallis, OR 97331-2119Tel. 541-737-2513Fax 541-737-0817e-mail puborders@oregonstate.eduPlease contact the above office forinformation on current publication pricesand availabilities and shipping and handlingcharges. Or, visit us on the Web athttp://eesc.oregonstate.edu/ © 2003 Oregon State University The Woodland Workbook is a collection of publications prepared by the Oregon State University Extension Service specifically for owners andmanagers of private, nonindustrial woodlands. The Workbook contains information of long-range and day-to-day value for anyone interested in wisemanagement, conservation, and use of woodland properties. Workbook publications are available in a 3-ring binder with tabbed dividers for eachsection. For information about how to order, and for a current list of titles and prices, inquire at the office of the OSU Extension Service that servesyour county.This publication was produced and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Extension work is a cooperativeprogram of Oregon State University, the U.S. Department of Agriculture, and Oregon counties.Oregon State University Extension Service offers educational programs, activities, and materials„without regard to race, color, religion, sex, sexualorientation, national origin, age, marital status, disability, and disabled veteran or Vietnam-era veteran status„as required by Title VI of the CivilRights Act of 1964, Title IX of the Education Amendments of 1972, and Section 504 of the Rehabilitation Act of 1973. Oregon State University Extension Service is an Equal Opportunity Employer.Published 1987. Revised May 2003. 8 THE WOODLAND WORKBOOKbamboo sticks threaded through the Vexarmesh. Once the sites are free of snow in thespring, inspect the tubes for distortions orconfiguration to protect the seedlings. 1.Managing grass and forb vegetation to2.Selecting and applying appropriate3.Assessing effectiveness of your control Sources of supplyHere are some major manufacturers ofprobe-baiting dispensers and burrowbuilders. This list isnt exhaustive, and itsnot an endorsement by the Oregon StateExtension office that serves your county fora list of nearby distributors.Probe-baiting dispensersRCO, Inc.Tel. 541-995-7799Burrow buildersRCO, Inc.(address and phone as above)All American Ag724 Woodard CanyonTouche, WA 99360Tel. 509-394-2910 For further informationdeCalesta, D.S. Controlling Pocket GopherDamage to Agricultural Crops, EC 1117.1999. Corvallis: Oregon State UniversityOrder from:Publication OrdersOregon State University422 Kerr AdministrationTel. 541-737-2513Fax 541-737-0817Please contact the above office forinformation on current publication pricesand availabilities and shipping and handlingcharges. Or, visit us on the Web athttp://eesc.oregonstate.edu/ © 2003 Oregon State University managers of private, nonindustrial woodlands. The Workbook contains information of long-range and day-to-day value for anyone interested in wisemanagement, conservation, and use of woodland properties. Workbook publications are available in a 3-ring binder with tabbed dividers for eachsection. For information about how to order, and for a current list of titles and prices, inquire at the office of the OSU Extension Service that servesThis publication was produced and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Extension work is a cooperativeRights Act of 1964, Title IX of the Education Amendments of 1972, and Section 504 of the Rehabilitation Act of 1973. Oregon State University Extension Service is an Equal Opportunity Employer.Published 1987. Revised May 2003. Archival Copy. For current information, see the OSU Extension Catalog:https://catalog.extension.oregonstate.edu FOREST PROTECTION 7 €Wea€Re€Be Applying controlsChristmas tree plantationsMany plantation sites were grass fieldsbefore being planted to conifers. Such sitesoften provide excellent food and cover forgophers. Managing grass and forb vegeta-forbs and grasses, the fewer gophers therewill be.However, dont plant such sites until atleast 6 to 12 months after you remove grassYou can discourage gopher entry into thesite by maintaining a buffer zone free ofof plantations. However, this may not bepractical or feasible.After youve controlled grass and forbvegetation, periodic site inspections willreveal anygopherinvasion.thesepromptly bybaiting, orboth. If atree planta-tion isinfested,applyingburrowbuilder (seethe quickest and cheapest solution.Forest plantationsManaging vegetation is a key to keepinggopher damage to a minimum. If possible,eliminate foods and cover from regenera-tion sites through burning and/or herbicideuse. If you can manage the vegetation ingopher invasions. You can treat thesepromptly and efficiently with hand baiting,For regeneration sites with establishedpopulations, the traditional control methodsional consulting service (usually twoapplications, with a follow-up to establishbuilder, youll greatly speed up the baitingprocess, and you may be able to bait aIn areas with high winter girdling lossand deer and elk damage, you might con-around the roots, extending 8 to 10 inchesbelow ground and extending 1 foot or moreground, to provide dual protection againstbrowsing by deer and elk and against winterVexar tubing tends to collapse from theweight of snow, and snow movement tendsanswer is to fix the tubes in place with two Archival Copy. For current information, see the OSU Extension Catalog:https://catalog.extension.oregonstate.edu 6 THE WOODLAND WORKBOOK dispensers work poorly insummer in soils with ahigh clay content becausethese soils when dry.For treating fairly flatareas of more thanthe burrow builderburrow builder behind atractor to create artificialbuilders automaticallydispense poison baits intoGophers investigate theseartificial burrows andbaits. If strychnine alka-loid is labeled for use withformulation is a restricted-use pesticide, and alicense is required to use it.Burrow builders disperse poison baits tentimes faster than hand baiting, but their use20 percent and soil relatively free of rocks,roots, and debris. The surface of the groundBurrow builders work well only withseed baits (pelleted baits jam in the device),of 25 horsepower.Like the probe-bait dispenser, the burrowbuilder is most effective when soil is moist,information on using the burrow builder,retreatment. Use the open-burrow surveyŽto measure reduction in gopher activityresulting from control methods.Establish 40 or more square samplingplots, 20 feet on a side and at least 100 feetwithin each plot. Examine the plots 24 to48 hours later to determine gopher activityplugged) and to record the number of plotswith gopher activity.Repeat the survey 1 to 2 weeks after youapply poison baits. To see how much youtreatment by the number before treatment,then multiply by 100. Rebait sites withManipulating habitat Gophers responddirectly to changes in availability of pre-and forbs by applying herbicides, thenumbers of gophers and the damage toif you plan to use vegetation managementto control gopher damage.Plant your conifer seedlings well afteryou remove grasses and forbs (even as longas 1 year). If you plant too soon, thetheyll devour every seedling.Habitat manipulation only reducesgopher numbers and damage, so youll needremaining gophers.Postharvest treatments before plantingshould create a favorable site for seedlingsBaitrelease leverHandleBaitcanisterProbeProbe endFigure 12.ÑBurrow building.ControllingPocket GopherDamage toAgriculturalWhen you baitsites larger thantime consumingto flatten andmound afterbaiting to deter-Bait canisterFrameShankCoulterwheelBait tubeTorpedoPressure wheelsBait meteringdevice Figure 11.ÑProbe-baitdispenser. Archival Copy. For current information, see the OSU Extension Catalog:https://catalog.extension.oregonstate.edu FOREST PROTECTION 5in the main runway.Trap in fall and springwhen the soil is softergophers are creatingnew mounds morezone 300 feet wideoutside the regenera-Trapping, likefumigating, doesntto return to eliminate surviving gophers.Just as you did for fumigating, flatten allretrap all burrow systems where themounds are rebuilt a week later.Poison baiting Poison baits areextremely effective for controlling gopherdamage. Grain baits containing 0.3 to0.5 percent strychnine alkaloid are availableBaiting is hazardous not only to smallmammals (such as voles, chipmunks, andbaits in gopher burrows but also to hawks,owls, and mammalian predators and scav-Hazard to predators and scavengers islow because most poisoned gophers will diethese animals. If seed baits are spilledabove ground and not cleaned up, they poseare highly susceptible to strychnine.Poison baiting is most effective in earlyspring, when natural gopher foods are inlow supply.Locate main runways with a probe.Rotate the probe in a circle several times toenlarge the hole, then remove the probe anddrop 1 teaspoon of bait into the tunnel.Close the hole with a dirt clod.If the opening is left open, the gopherwill plug the runway at that point, coveringthe bait. Never scatter bait around theburrow entrance„birds will be poisoned ifyou do. Make three to five bait placementsYou can bait with a probe-bait dispenser(Figure 11, page 6). This device cutsonly grain baits because pelleted baits will Figure 10.ÑCorrect placement of gopher traps.jam in probe-bait dispensers.Locate themain runwayprobe. Push abutton or leverser to release ameasuredinto the tunnel,then pull thethe ground.Cover thehole with arock or clod.Figure 9.ÑProbe used to locate gopher tunnel system. Footrest3Ú4" Gas pipe14"5"30"Round end5" Stake with flaggingMain runway Archival Copy. For current information, see the OSU Extension Catalog:https://catalog.extension.oregonstate.edu 4 THE WOODLAND WORKBOOKOpen the burrow down to the main runwayand place about 1 cup of dusting sulfur inthe burrow entrance. Turn the gas on fullforce and light it. The flaming propane willThe sulfur burns bests when you hold thetorch about 6 inches away. Thick, whitesoil. The sulfur burns up in about 30 sec-onds. Cover the burrow entrance with soilFumigating is time consuming, so use itonly when you need to treat areas less thannontarget animals because its used only inactive gopher burrow systems„andburrows. Fumigating, like other lethalcontrol methods, usually must be repeatedyou missed with thefirst application.To determinewhether you need toyou fumigate. Returnin a week and treatwhere the moundshave been rebuilt.They are a sign that you didnteliminate all gophers with thefirst treatment.Gophers from adjacent areaswill invade rapidly and usereinfestation, fumigate gopherburrows in a buffer area 300 feetsite.Trapping is effective buttime consuming, so trap smallareas (less than 5 acres) or inplaces where poison baits cantbe used. Follow up fumigatingto remove gophers resistant togas or baits.Use Victor or Macabee traps.Locate the main runway of the burrowarea between two adjacent fresh mounds.Youll know when you hit the runway4 inches in the ground. Dig an openingdown into the runway and place two trapsAnchor the traps with wire and flag themto make relocation easy and to preventopen; this will attract the gopher to the traparea. The gopher will be caught coming inopen runway.You may put traps in lateral runways atthe mouths of opened burrows, but yourFigure 8.ÑHand-held propane Ògopher gasser.ÓFigure 7.ÑLayout of plots on transect lines for assessing need to controlgopher damage. Individual plotTransect lineTransect line Propane gas(5-gallon L-P tank)10-foot flexibleL-P gas hose18-inch OD connector pipeBarrelValveHandle Archival Copy. For current information, see the OSU Extension Catalog:https://catalog.extension.oregonstate.edu FOREST PROTECTION 3Gophers system of mounds, earth plugs,and winter casts is distinctive. The moundis horseshoe- or fan-shape (Figure 5).and spread it around the opening (about2 inches wide) at one edge.Mole mounds look like those of pocketgophers, but they are volcano- rather thanThe mound pattern of pocket gophers isdifferent from that of moles. Moles push uplines, but gophers cluster mounds in irregu-lar groupings (Figure 6).Voles burrow but do not mound dirt atthe tunnel entrance. Their openings (aboutnected by aboveground trails.Assessing the need for treatmentDetermining the need to control gopherdamage should be part of your harvest andreforestation planning. The standardmound survey, which is an index of gophernumbers.To assess gopher numbers, check plots ofone-tenth acre (square areas 20 feet on aacre plot per acre of regeneration site isrequired to accurately assess the need foron lines (transects) across regeneration sitesso that adjacent plots are at least 150 feetBegin your control measures on sites upto 2 years old if 25 percent or more of the3 to 5 years old if 40 percent or more of theplots contain active mounds.Damage control techniquesYoull achieve maximum effectivenessof most control techniques if you canemploy them before you plant seedlings.Most forest managers are willing to applycontrol techniques before planting only ifdamage is very likely„thats why itsimportant to conduct your mound survey.Where its possible, combine severalcontrol techniques. This will give betterFumigating Fumigants (cartridges andpellets) release poison gases (carbongophers burrow system. They are mostsqueeze a handful, it forms a ball ratherthan crumbling.Fumigants wont work when the soil isdry because the gas leaks. Fumigants workeasier to spot then, too).Open the burrow tunnel down to themain runway with a shovel or trowel. Ignitepellets) 6 to 10 inches down the openedentrance and cover with several shovelfulsof soil to block escape of poison gas.If the gas doesnt kill the gopher, thegopher usually clears its runway of residualAnother way to gas gophers is to use ahand-held propane(Figure 8, page 4)and dusting sulfur.Figure 5.ÑA typical gopher mound.Figure 6.ÑMole mounds are easily distinguished from pocketgopher mounds. MolePocket gopher Archival Copy. For current information, see the OSU Extension Catalog:https://catalog.extension.oregonstate.edu 2 THE WOODLAND WORKBOOK They spend most of theirlives in their extensiveburrow systems, whichunderground and cancontain over 500 feet ofGophers feed mostlyabove ground on grassesburrow opening. They alsofeed underground on thetrees. Most girdling ofseedlings and saplings is inMating is in early spring; four to eightyoung are born 3 weeks later. In earlysummer, the young are driven from thesystems. Gophers breed at 1 year of age,usually have only one litter a year, and haveGopher density varies with habitat con-ditions, ranging from four to twenty persystems are shorter and gopher densities arehigher. Control programIdentifying the pestIdentification is based on characteristicsof damage and burrow systems. Physicalunique. Gophers clip roots and rootlets,leaving only the main stem of the seedlingseedlings wilt and turn brown, and theseedling can be pulled out of the groundGophers may pull entire seedlings belowground. They girdle seedlings and saplings,saplings look sculptedŽ1‡16 inchwide. A gopher burrowingthrough snow can girdleconifer stems as high assnow depth, which may be7 feet or more above ground.Voles, like pocketgophers, damage seedlingsby girdling, but their teethare so small that gnawedbark looks fuzzy. Voletoothmarks are about1‡32 inch wide.Porcupines occasionallygirdle conifers at groundlevel, but their toothmarks(1‡8 inch wide) are twice aslarge as those of gophers.Figure 2.ÑEarthen ÒcastsÓleft above ground by gophersFigure 3.ÑTypical gopher clipping damageFigure 4.ÑA ÒsculptedÓington during winter, when the gophersburrow system extends above ground intoThe soil that gophers push out into thesesnow tunnels forms the curious casts orground after snowmelt (Figure 2).Gophers inhabit small forest openingswhere they find their preferred foods. Suchcreated by clearcut logging.Within months, gophers invade regenera-tion sites from adjacent clearcuts or mead-ows. Gophers can travel more than 300 feetabove ground and 2,500 feet under snowopenings to new clearcuts.Gophers are solitary exceptduring the breeding season. NormalGopher-clipped Archival Copy. For current information, see the OSU Extension Catalog:https://catalog.extension.oregonstate.edu EC 1255 Â¥ Revised May 2003 $2.50 FOREST PROTECTION Gopher habits and habitat..............1Control program...........................2pest......................Assessing the need for treatment...techniques...........Applying controls..........................7plantations.............Summary....................................8Sources of supply.........................8For further information..................8 David S. deCalesta, former Exten-sion wildlife specialist, and KimForestry, both of Oregon StateUniversity; revised by Nancy Allen,Oregon State University.ocket gophers(or just plaingophersŽ)Pgirdle (remove bark from) the bases of conifer seedlings and saplings,causing significant economic losses.This publication will help you design a program to reduce or eliminategopher damage to seedlings and saplings in your forest plantation orFirst, we describe pocket gophers, their habits, and habitats. Then wediscuss procedures for controlling pocket gopher damages„controluse under a variety of tree-growing situations. Gopher habits and habitatThree species of pocket gopher can damage conifer seedlings. The twosmaller ones, the northern pocket gopher and the Mazama pocket gopher,belly. The northern gopher is found east of the Cascade Mountains inWashington west of the Cascades.The Camas pocket gopher is similar looking, but larger (10 to 12 inches)than the two others. It lives in Oregon north of Eugene in the WillametteAll are easily identified by their fur-lined external cheek pouches andlarge orange front teeth, which are used to clip roots and dig tunnels. They Figure 1.ÑTypical Oregon pocket gopher.damage conifer seed-lings on thousands ofacres in Washington,Idaho, and Oregoninvade clearcuts andclip (cut off) roots or Archival Copy. For current information, see the OSU Extension Catalog:https://catalog.extension.oregonstate.edu