共查询到20条相似文献，搜索用时 46 毫秒
1.
2.
草河口地区红松人工林结实规律的初步研究 总被引：2，自引：0，他引：2
一、前言红松天然林多分布于偏远林区,种子采集、运输皆感不便;加之天然林结实较晚,并具有明显的结实间隔期,这在保证造林所需种子的供应上,存在一些困难。为此,我们利用草河口地区人工林较多、年龄较大、生长发育较好的有利条件,从1958年起开展了红松人工林的物候观测,1959年结合物候观测又进行了红松结实规律和母树林培育的试验研究工作,借以探讨红松结实的规律和培育母树林的方法,为逐步解决红松种源问题,提供一 相似文献
3.
4.
5.
优良红松坚果型优树的选择方法(英文) 总被引：3，自引：0，他引：3
于1988-1998 年对长白山、小兴安岭和完达山地区天然红松林以及黑龙江省鹤岗地区人工红松林结实量进行了实地调查和测定。根据调查和测定数据，对红松结实特征，包括结实量、球果长度、球果数量、出种率，种子千粒重、种子产量、种子大小、种子空实率、球果虫害率、结实指数等，进行分析方差分析、多重比较和逐步回归，得出各项结实因子对结实量的贡献率，将球果长度、千粒重和出种率确定为优树选择的重要指标，然后采用加权系数法确定红松坚果型优树，并制订出天然红松林坚果型优树标准和红松人工林坚果优树标准。本项研究为建立红松坚果园选择优树提供了方法和标准。 相似文献
6.
红松Pinuskoraiensis常绿乔木。材质轻软、抗压力强、耐腐朽。是我国东北大小兴安岭、长白山林区主要用林树种之一。柴河林区红松人工林面积占造林总面积的30％～40％，大部分分布在中、深山区的采伐迹地上。由于这些地区气候湿润，天然下种力强，加之采伐后保留的部分天然幼苗、幼树，以及造林后天然的杨、作树生长速度快，很快将人工红松林处于林下被压状态，生长量下降，病虫害增多，人工造林成果遭受了一定损失。因此，及时对红松人工成林进行透光抚育，调整天然林木在人工成林中的比例，使红松林木逐渐占据优势地位，形成以红松为主的… 相似文献
7.
刺槐是绥中县的主要造林树种之一,每年造林占全县造林总面积的60～70％,育苗用种5～6千斤。六十年代初基本可以自给,可是目前虽然可结实的母树林已增加到4000亩,采收的种子却满足不了需要,仍有大部分需由外地调入。据调查,主要由刺槐种子小蜂为害所造成,在绥中该虫被害率一般达80％以上,使被害母树大部分丧失了采种价 相似文献
8.
提高红松人工林种子经济效益研究 总被引：3，自引：0，他引：3
根据红松人工林结实与生长、分杈的关系，采取不同的修箭技术，可大幅度提高单位面积上的种子产量。从而总结出提高红松人工林种子经济效益的有效技术措施。 相似文献
9.
黑龙江省林口林业局到２０００年人工更新造林保存面积，再次率先成为第２个百万亩人工林的森工企业。人工红松林面积４万ｈｍ２，早期营造的已开花结实。林口林业局将红松资源优势实施果材定向培育作为“缓危解困”的一项重要措施。但由于人工红松林早期杈干使结实减少了８５％以上，严重的近于绝产，出材率降低了２９．３７％～６３．６４％，严重阻滞了“兴企富民”目标的实施。该局从生产实际需要出发自选《人工红松林杈干形成与控制》项目进行研究。历经３年，该局在省、总局、管局、东北林业大学的支持与指导下，完成了该项的研究。提… 相似文献
10.
红松粗皮、细皮类型的初步研究 总被引：2，自引：0，他引：2
一、前言红松的材质优良,种子含油量很高(70%以上),营养丰富,是我国东北长白山林区和小兴安岭林区的主要珍贵树种。它不仅是这两大林区的优势树种和主要更新树种;同时也是更广阔地区人工造林的很有前途的树种,辽宁省草河口试验林场的红松人工林的生长速度为天然林内红松的五倍即是—例。笔者几年来参加红松育种工作、红松林结实调查工作和长白山林区红松,落叶松采种工作。在工作中发现了红松的树皮有两种类型,即粗皮(厚皮)类型和细皮(薄皮)类型。粗皮红松和细皮红松不仅在树皮的形态和厚度上有显著不同,它们的生长,发育,干形和树冠都有很大变异,从经济意义上看它们的生长速度,结实量和种子品质,合油量也有所不同。现将调查资料加以整理、分析,并提出初步看 相似文献
11.
杨、桦林抚育改造技术研究 总被引：1，自引：0，他引：1
通过对黑龙江省东部山区10个林业局、427块标准地、1712株解析木的调查研究，得到了杨、桦林的树高、胸径和材积生长曲线，并编制了杨、桦林的抚育间伐控制图。 相似文献
12.
《Forest Ecology and Management》2006,221(1-3):13-26
Effective utilization of a patch or cluster approach to growing aspen-white spruce mixtures in the boreal forest requires an understanding of how the faster growing aspen patches influence microclimate and spruce growth in adjacent spruce patches. In this paper we examine, how young (11–13 year old) aspen (Populus tremuloides Michx) patches influence microclimatic conditions in adjacent openings and how these are reflected in the growth of white spruce (Picea glauca [Moench] Voss) on three boreal mixedwood sites in west-central Alberta, Canada. Light levels increased continuously across the aspen stand boundary and reached maximum levels within the opening, while soil moisture was highest near the edge of the opening and then decreased with distance into the aspen stand or into the adjacent opening north of the aspen stand. Light levels were reduced over a greater distance when moving north from aspen stand edges compared to openings located south of the young aspen. These young aspen stands provided growing season frost protection within one tree length from the edge. The growth of white spruce was positively related to initial crown size and either light levels or distance from the edge. Stem volume growth was best predicted by initial tree size and the light levels at the midcrown of seedlings. 相似文献
13.
14.
毛竹笋材两用林配方施肥效应研究 总被引：6，自引：2，他引：4
对毛竹笋材两用林的配方施肥试验结果表明，施肥区的笋材产量与不施肥区相比有明显增加。施用4种肥料3a累计平均净增产鲜竹材6603.3kg/hm^2、鲜竹笋544kg/hm^2。每公斤肥料（按有效成分N，P，K计算）年均净增产竹材7.7kg、鲜笋0.64kg。最佳施肥配方为A2B1C2D3，即每公顷施菜子饼1125kg,N肥150kg,P肥56.3kg,K肥75kg。其影响次序为A＞C＞D＞B。使用这个配方竹林生产力量高，其中年均产竹材21.96t/hm^2、竹笋1.65t/hm^2，收入1.074万元/hm^2。 相似文献
15.
《Scandinavian Journal of Forest Research》2012,27(1):38-47
The objective of this study was to quantify the effects of high nitrogen (N) inputs on N cycling in a 35–45-yr-old Scots pine (Pinus sylvestris L.) forest. Nitrogen was added annually (single doses) as NH4NO3 in doses of 0 (N0), 30 (N1) and 90 (N2) kg N ha?1 yr?1. The only N input to the N0 plots was atmospheric deposition of 10 kg N ha?1 yr?1. The N cycle in these plots was tight, with almost complete retention of the incoming N. In the N1 plots the N retention was 83% after 9 yrs of N addition. The trees were the major sink, but the soil also contributed to the N retention. In the N2 plots the N retention was 63%, being mainly accounted for by accumulation in the soil. The leaching of N from the N2 stands was as high as 35 kg N ha?1 yr?1. The N2 system was N saturated. 相似文献
16.
Three 21-year-old Appalachian hardwood stands were strip cut using three cutting widths (2.4-m, 3.7-m, and 4.9-m) and allowed to resprout. One year after strip cutting, we examined the vegetation response within the harvested strips relative to non-treated control areas, focusing on the sprouting ability of young hardwood stems and the herbaceous component for wildlife habitat. Results indicate the width of the strip cutting significantly affected the amount of biomass produced from stump sprouts (p = 0.042) and influenced species composition. Shade-intolerant species accounted for more of the biomass production within the wider cut strip widths, while shade-tolerant and shade-intermediate species were more prominent within the narrower cut strips. Cut strip width did not have a significant effect on the biomass of new seedlings germinating after the cuttings. Herbaceous vegetation was greater within the 4.9-m cut strips than in the control plots (p = 0.046); however, the amount of herbaceous biomass produced did not vary among months during the first growing season. Overall, our initial results suggest that strip cutting can provide benefits to wildlife and can possibly provide for additional biomass as the regrowth is harvested in the future. 相似文献
17.
Dryocosmus kuriphilus Yasumatsu, an invasive gall wasp originating from Asia, is the latest serious pest attacking Castanea sativa Mill. in Europe; the negative effects on fruit and wood production are considerable. The most effective defense strategy is biological control, but parasitoid effectiveness requires at least 6–10 years to reduce damage to acceptable levels. In Italy, prolonged productivity losses could adversely affect human activity in chestnut orchard stands, resulting in negative socio-economic and hydrogeologic consequences. Thus, it is necessary to quickly reduce the impacts of the infestation to avoid degradation of chestnut stands during the time delay required for parasitoid efficiency. We examined green pruning as a means to reduce negative impacts of gall wasps and stimulate healthy shoots in a young chestnut coppice in Central Italy. Two different pruning cuts (Long- and Short-cut) on growing shoots and four timings of application were tested. The development and phytosanitary status of nodes was observed over 2 years on pruned and control sprouts. Pruning was effective in reducing gall wasp damage though responses varied among pruning techniques and application times. Long-cut pruning made in spring during the full growth phase induced a higher number of new and better-developed shoots. Pruning during the end of the egg-laying period of the gall wasps promoted development of only healthy new shoots. Our results indicate that is possible, by choosing the best combination of time and technique, to identify a pruning method useful to maintain growth and development of C. sativa stands threatened by D. kuriphilus.
相似文献18.
《Forest Ecology and Management》1997,97(3):231-235
A stemflow measurement technique is described, based on: (1) correlations between stemflow volume and tree diameters at breast height (DBH), determined on the basis of a relatively low number of tree samplings; (2) the distribution of trees in the stand relative to their DBH. Stemflow for trees in a stand (mm) can thus be determined from total rainfall (mm). The results were compared to those obtained with two other stemflow determination techniques. The proposed method was found to be more reliable, precise and easier to apply than the standard methods. 相似文献
19.
《Scandinavian Journal of Forest Research》2012,27(1-4):239-251
20.
《Scandinavian Journal of Forest Research》2012,27(3):214-226
Abstract The quantitative effect of pine-dominated edge stands in southern Finland on the density and growth of pine saplings was addressed in the study. The cumulative effect of a mature edge stand on the development of a pine sapling stand with variable cutblock sizes was also estimated. The data were acquired from 10 study sites with a Scots pine sapling stand with a current dominant height of 1–6 m and an adjoining middle-aged to mature edge stand dominated by Scots pine. Tree level models were constructed to describe and simulate the structure and development of the sapling stands. The results indicated that dividing an average regeneration area (2 ha) into smaller cutblock units (1.0–0.5 ha) appreciably increased the edge stand effect. Total stand volume growth was 6% lower on 1 ha cutblocks, and 31% lower on 0.5 ha blocks, than on 2 ha blocks. 相似文献