562 JOURNAL OF FORESTRY tion, furrow sliceplanting may prove of impor- cockBranch Experiment Station, in centralWis- tance. It is hardly justifiableunder the condi- consin.Jack and red pine seedlingswere planted tions studied,especially because the plantingis in shallowfurrows, deep furrows, on top of the costlyand requiresvery carefulsupervision. furrow slice, in slits without scalping,and in Planting in slits without scalpinghas shown holes using spadeand additionalhumus soil. the lowest survival and practicallythe lowest Each treatmentwas replicated16 times with 40 heightgrowth of both jack and red pine. This treesof eachspecies per sampleplat. can easilybe explainedby the unfavorabledis- Plantingin deepfurrows under the conditions tribution of rootsand the competitionof the sod studiedhas given the best resultsin regard to Downloaded from https://academic.oup.com/jof/article/40/7/562/4706695 by guest on 28 September 2021 vegetation. both survivaland the rate of growth. Slit plant- Plantingin holeswith additionof humussoil ing has shownthe poorestresults. in the caseof jack pinegave results nearly identi- showeda fair degreeof survivalwhen planted by cal with those obtained with the shallow furrow all other methods.A very low survivalof red planting.The verylow survivalof red pineshown pine wasobserved in plantingon top of the fur- by this mostelaborate and expensivemethod is row slice. The mostcareful and expensivespade puzzling.Whatever the reasonsmight be, plant- plantingfailed to produceresults better than were ing in holeson the soil studiedfailed to justify obtainedby any other methodexcept the slit the extra labor. planting. No significantdifference was observed in survivalor in the rate of growthin furrows SUMMARY plowedin differentdirections. The differencein A numberoftree planting methods have been averageheights of variouslyplanted trees did not investigatedon the exposedarea of a depleted exceeda few inches,and was found to be of ques- outwashsandy soil (Plainfieldsand) at the Han- tionablestatistical significance.

Mortality of Reproduction Defoliated by the Red-headed Pine ( !econtei Fitch) J. A. Beal Duke University

Reports on the killing of young pines as a result of defoliation by the red-headedpine sawfly are not uncommon. Some observationson the amount of such injury required to kill pines are here report.ed.Additional information on relativesurvival and susceptibilityof •shadedand unshaded trees is also presented.

ERIODICoutbreaks of the red-headed pine two hundredsmall infested pines varying from 1 sawfly(Neodiprion lecontei Fitch), a pest to 5 feet in heightwere tagged in the Duke For- of young pines in easternUnited States, est in Octoberafter feeding by the larvae had sometimes result in considerable losses in refor- beencompleted. When the trees were numbered, ested areas. A local outbreak of this in the speciesand height were recordedand they someof the youngstands of shortleafpine (Pinus were placedinto two broad groupsaccording to echinataMill.) and loblolly pine ( the amountof exposureto directsunlight. They Linn.) in the Duke Forestin 1939 providedan were further subdivided into four classes based opportunityfor observationson the severityand upon the estimatedamount of defoliation (See effectsof late summerdefoliation by this insect. Table 1). Becausethe larvaeusually destroy the Middleton x found that effects of defoliation be- needlesdown to the fasciclesheath only, it is fore late summerwere especiallysevere. believedthat foliage lossescan be determined In orderto determinethe amountof sawflyde- fairly accuratelyafter the feedingis over. Since, foliation necessaryto kill young pines, and to in the final analysis,no differencesin survival learn whetheror not any correlationexisted be- ability were found which could'be attributedto tweenamount of shadingand survival of trees, height or speciesthe effectof thesefactors has been omitted. •Middleton, William. A sawfly injurious to young pines. U.S. Dept. Agric. Farmers Bull. 1259. 1927. The numberedtrees were reexaminedin May RED-HEADED PINE SAWFLY 563

TABLE 1.---MORTALITY OF PINES ATTACKED BY THE RED-HEADED PINE SAWFLY

Class 1 Class 2 Class 3 Class 4 Percent of defoliation ...... 0•25 26--50 51-75 76--100 Percent Percent Percent Percent No. trees dead No. trees dead No. trees dead No. trees dead Shaded trees ...... 18 0 15 33.3 20 55.0 57 96.5 Unshaded trees ...... 16 0 19 0 17 0 38 84.2 Totals ...... 34 0 34 14.7 37 29.7 95 93.7

and again in August1940 and survivalcounts It would appear from the above data that Downloaded from https://academic.oup.com/jof/article/40/7/562/4706695 by guest on 28 September 2021 made. Sinceless than 5 percentof the mortality shortleafand loblollypines, even where growing occurred between these two examinations it was in the opencannot endure a lossof 76 percentor believedthat very little additionalloss, which moreof their foliageby the red-headedpine saw- could be attributed to the effects of the 1939 saw- tty. If shadedsome will die after as little as 50 tty defoliation,would take place. The data are percentdefoliation by this insect.. Many trees summarized in Table 1. whichsurvive partial defoliationare stuntedand Opengrown pines appeared to be better able misshapenand it is doubtfulthat suchtrees will to withstand defoliation than did those which producematerial of commercialquality. It is werecompeting with hardwoodsand wereeither noteworthythat on someof the plotswhere com- partially or completelyovertopped. It is quite petitionwith hardwoodsis greatestall of the probablethat root competitionrather than light pineshave been eliminated through a singlelate competitionmay havebeen the importantfactor summerdefoliation by thissawtty. It is possible, here. In any eventno mortalityresulting from a however,that the 'may have quickly singlelate summerdefoliation of unshadedpines brought about a changewhich in time would wasobserved except in caseswhere more than 75 have been effected without their aid. percentof the foliagehad beendestroyed. A mor- A goodmeasure of the percentageof standin- tality of 84.2 percentoccurred on open grown festedwas obtainedby Jestera in the fall exami- pineswhich had lost from 76 to 100 percentof nation of somecutting plots in the samearea. their foliage. No trees surviveda singlecom- His countsshowed that 45 percentof the 4,628 plete defoliation. pineson 1,122milacre plots had losttwo-thirds Shadedpine. s, by contrast,exhibited a greater or moreof their foliageas a resultof the feed- mortalitywithin eachclass. No mortalitywas ing of the larvae. Theserecords show further foundin class 1 in which the needle loss did not that in areascleared to free the pines(unshaded exceed25 percent. It first showedup in class2, trees) the number heavily attackedby sawtty where,with defoliationvarying between26 and larvaewas only 23 percentof the total,while on 50 percent,one-third of thetrees died. The num- the remainingplots where hardwoodsovertop ber of deadtrees resulting from larval feedingin- the pinesover 53 percentof themhad beentwo- creasedwith the greaterdestruction of foliage, thirds or more defoliated. It thereforeappears and, in classes3 and 4, the mortalitywas 55 and that pinesgrowing in the openare lesssubject 96.5 percent,respectively. to attackby the red-headedpine sawtty, than are The heavymortality in caseswhere only part shadedones and as alreadypointed out, such of the foliagewas consumed can probably be ex- pines,if attacked,are ableto withstandmore se- plained by the fact that sawttylarvae of this vere defoliation than are shaded trees. speciesoften do considerablefeeding on the twigs by biting out large piecesof outer bark and 2Jester,J. R. Memorandumon a sawflyoutbreak in pine reproductionin clearcut patchesin Stand6, Com- phloem. This type of injury was commonly partment 60, Durham Division, Duke Forest, Dec. 12, notedbut no measureof it wasattempted. 1939.