曲水园古松柏生长环境的土壤质量与评价

为制定促进古松柏良好生长及复壮措施提供科学依据,对曲水园古白皮松、古桧柏进行了土壤质量调查与分析,结果表明：古白皮松、古桧柏生长环境的土壤pH值较高、而土壤的EC值、有机质和速效氮的含量偏低,由此会对古白皮松、古桧柏的生长造成不利影响;经测试,古白皮松和古桧柏土壤中的有效磷含量达丰富水平,土壤中的微生物含量,古白皮松比古桧柏要高。对存在的问题提出了相应的改良措施。     

非稳态法测定马尾松扩散系数

采用非稳态法在一定的实验条件下测定了马尾松的水分扩散系数,并且探讨了不同干燥介质温度、不同初含水率、不同纹理方向对扩散系数的影响。实验结果表明：干燥介质温度越高,扩散系数越大;初含水率越高,扩散系数也越大;木材纵向水分扩散系数远大于横向水分扩散系数,其比值介于5～7之间;径向水分扩散系数略大于弦向水分扩散系数,其比值约为1～1．5。     

分子蒸馏富集华山松籽油中亚油酸的研究

对华山松籽油先进行乙酯化,然后利用刮膜式分子蒸馏器对其中的亚油酸进行富集.考察了进料速率、进料温度、蒸馏温度和刮膜转速对华山松籽油中亚油酸分离效果的影响.结果表明,刮膜式分子蒸馏技术提纯华山松籽油中亚油酸的最佳工艺条件为:蒸馏温度105～115 ℃,进料速率60～80 mL/h,进料温度55～60℃,操作压力1.0 Pa,刮膜转速200 r/min.经过四级分子蒸馏,可以将华山松籽油原料中的亚油酸纯度由原来的63.3%提高至82.7%.     

马尾松单板脱脂工艺的试验研究

采用碱液对马尾松单板进行脱脂处理,通过正交试验设计以脱脂率和抗拉率作为综合指标得出最佳的脱脂工艺,以期为马尾松单板的后续加工利用提供依据。结果表明:碱液脱脂能够有效降低马尾松单板中的脂含量,同时又不至于使单板强度降低太多;最佳的脱脂工艺为:药剂浓度0.5%,温度80℃,处理时间4 h,浴比为4。     

马尾松纯林不同地表覆盖对产流产沙的影响研究

马尾松林地水土流失严重,为了研究马尾松林下种植植物的水土流失防治效果,选择4种不同郁闭度的林地设计3种试验小区,其中两个小区分别种植百喜草、胡枝子,与保留的自然小区进行对比试验,分析了不同郁闭度对小区产流及侵蚀产沙的影响。结果表明,当马尾松纯林地郁闭度低于0.3时,不同郁闭度间的细微差异对小区产流和产沙的影响不显著;植被盖度对小区产流和产沙的影响呈现一定规律性,当自然小区植被盖度低于30%时,产流、产沙量随植被盖度增大而下降;百喜草小区植被盖度达到45%以上时,形成乔草复层结构,比单一草被覆盖保水减蚀效果更好,且与是否有枯落物覆盖等因素有关;胡枝子小区产流、产沙量与植被盖度、乔灌草立体结构是否形成有关,人工种植胡枝子更有助于马尾松纯林形成乔灌草立体结构群落。     

Interspecific inhibition of the response of the bark beetles,Dendroctonus brevicomis andIps paraconfusus,to their pheromones in the field

Ponderosa pine logs infested withIps paraconfusus males inhibited the attraction ofDendroctonus brevicomis in the field to either attractive logs cut from a ponderosa pine tree under attack byD. brevicomis or to their synthetic pheromones,exo-brevicomin, frontalin, and myrcene. Logs cut from trees under attack byD. brevicomis inhibited the response ofI. paraconfusus to logs infested with maleI. paraconfusus.Exo-brevicomin, frontalin, and myrcene did not inhibit their response but verbenone did. Verbenone was found in maleD. brevicomis dissected from attractive logs under attack during the same time the response ofI. paraconfusus was inhibited by these logs.Trans-verbenol andexo-brevicomin were found in femaleD. brevicomis while verbenone,trans-verbenol, and frontalin were found in maleD. brevicomis in relatively large amounts near the beginning of the aggregation phase of host colonization. All of these compounds had decreased at a similar rate 5 days later. This gradual decrease inexo-brevicomin and frontalin probably caused the observed reduction in attraction. The ecological significance of these compounds in relation to termination of the aggregation phase ofD. brevicomis and reduction of interspecific competition is discussed.Coleoptera: Scolytidae. This paper is based in part upon a dissertation submitted by J.A.B. to the University of California, Berkeley, in partial fulfillment of the requirements for the PhD in entomology. These studies were supported in part by the Rockefeller Foundation; U.S. Forest Service; Regional research Project W-110, S.E.A./ U.S.D.A.; and the National Science Foundation and Environmental Protection Agency through a grant (NSF GB-34719/BMS 75-04223) to the University of California.     

(1S,2R,4S,5S)-angelicoidenol-2-o-β-d-glucopyranoside—A moose deterrent compound in Scots pine (Pinus sylvestris L.)

Hydrophilic extracts of Scots pine (Pinus sylvestris L.) twigs have been investigated for palatability to moose in feeding experiments. The predominant repellent effect was observed from the 2-O--d-glucopyranoside of the monoterpene (1S,2R,4S,5S)-angelicoidenol. Of other isolated and tested substances, only taxifolin-3-O--d-glucopyranoside had a deterring effect. One fraction-containing mainly aliphatic compounds-also had a strong effect, but the effect was lost after further fractionation. Tannin-containing fractions had no effect. Angelicoidenol glucoside has not previously been reported fromP. sylvestris. The results are discussed in view of phenols as defense compounds.     

Physico‐Mechanical Properties and the TVOC Emission Factor of Gypsum Particleboards Manufactured with Pinus Massoniana and Eucalyptus Sp.

The effect of wood species on the TVOC emission factor and the physico‐mechanical properties of GPBs is investigated. Of the two wood species, the water absorption was higher for the GPBs made using Eucalyptus sp. than for those using Pinus massoniana. The Eucalyptus sp. GPBs pressed at room temperature, 40 and 60 °C all demonstrated higher moisture absorption than commercial GPBs. The TVOC emission factor decreased with increasing press temperature, especially for Eucalyptus sp. but remained under ‘excellent’ grade as defined by the KACA. From these results, GPB with higher content of wood particles should be considered for the replacement of wood‐based panels such as particleboard and medium density fiberboard (MDF).