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贵州马尾松建筑材林优化栽培模式研究 总被引:9,自引:1,他引:8
在建立生长收获模型系统基础上 ,通过对立地、种源、整地、施肥、间伐等对生长影响的研究 ,建立了马尾松人工林经营模型系统。根据培育目标 ,用经营模型对众多营林方案的采伐年龄和经济结果逐一进行了优化和比较 ,为不同指数级选出了优化栽培模式。结果表明 :按优化栽培模式经营大、中、小径材 ,可比现行采伐年龄分别缩短 4~ 6年、9~ 1 2年、8~ 1 2年 ;内部收益率分别比常规模式提高 1 6~ 2 8、1 8~ 4 1、2 1~ 4 0个百分点 ,净现值分别增加 1 30 0~ 2 790、2 0 0 9~ 34 47、1 1 37~ 31 6 8元 /hm2 ;优化模式的内部收益率均大于 1 2 %。培育建筑材 ,高初植密度并不能取得高收益 ,合理间伐可提高经济效益。主要模型均通过了显著性检验和残差分析 ,所建经营模型系统和选出的优化栽培模式可在研究区内应用 相似文献
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在 6~ 18年生湿地松、火炬松用材林中布置了 10片间伐强度试验林 ,对不同间伐处理的林分测树因子和间伐作业经济效益进行了分析 ,最后确定了两个树种工业用材林密度调控方案。正常情况下 ,2 0 0 0株· hm-2以下密度林分 8年生后间伐即有收益 ,而首次间伐龄应在 12年生之前方能使保留木生长速率获得提高。通过间伐可使立木规格材出材率略有提高 ,但伐后 4~ 6 a间 ,立木蓄积量、规格材出材量、林分总收获量基本上随间伐强度加大而减少 ,两次间伐的间隔期至少应在6 a以上。综合考虑立地条件、生长效应和经营目的 ,认为两个树种工业用材林营建应选择立地指数14~ 18林地 ,培育纸浆材林分 ,初植密度 2 0 0 0~ 16 6 7株· hm-2 ,或 15年生主伐 ,或 8~ 10年生作中强度间伐至 12 0 0株· hm-2左右 ,18~ 2 0年生主伐 ;培育建筑材 ,初植密度 16 6 7~ 1111株·hm-2 ,10~ 12年生第 1次间伐至 110 0~ 80 0株· hm-2 ,16~ 18年生第 2次间伐至 80 0~ 50 0株·hm-2 ,2 0~ 2 5年生时主伐 相似文献
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不同造林密度华山松人工林抚育间伐强度的选择研究 总被引:1,自引:0,他引:1
为确定不同造林密度形成的人工华山松林的合理抚育间伐强度和具体间伐措施,对不同间伐强度下2种不同密度人工华山松林的林木平均胸径、树高和单位面积蓄积变化进行研究。结果表明,一般密度华山松人工林间伐强度效果为:30%>35%>25%>45%>50%>20%>60%>10%>0%,保留株数以1 830株/hm2左右最好,在抚育间伐实施中采取3株中选伐1株与4株中选伐1株交替使用措施效果最好;密植华山松人工林间伐强度效果为40%>45%>35%>50%>30%>60%>25%>20%>10%>0%,保留株数以2 985株/hm2左右最好,在森林抚育实施中采取2株中选伐1株与3株中选伐1株交替使用效果最好。 相似文献
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为探索湿地松优质高产纸浆原料林密度控制与管理技术,进行了不同初植密度造林与间伐试验.试验结果表明:8a生、12a生密度试验林不同密度林分胸径、树高、蓄积量和总产量有极显著差异,8a生密度试验林不同密度林分木材性有极显著差异.林分在8a生时,平均树高生长效应是林分越密树高越高,林分平均胸径生长效应是林分密度越小胸径越大,蓄积量的生长效应是林分越密蓄积越大,木材材性是以中等林分密度质量最好.营造湿地松高产优质纸浆原料林适宜初植模式为2 m×2 m、2 m×2.5 m,即初植密度分别为2 505株/hm2和1 995株/hm2,此时2 505株/hm2林分按下层间伐方式间伐25%、1 995株/hm2林分按下层间伐方式间伐20%后4 a(林分年龄为12 a),这二种密度林分蓄积分别为224.08 m3·hm-2和206.64 m3·hm-2,蓄积加间伐材材积的总产量分别为244.56 m3·hm-2和218.72 m3·hm-2.为培育出质量和产量兼优的湿地松纸浆原料林,当林分生长到8 a生时,应及时地进行一次抚育间伐,间伐强度为20%~25%. 相似文献
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1 材料与方法在绥棱、通化、南岔、美溪、东京城、桦南等地调查红皮云杉人工林临时标准地 130余块 ,标准地分布在各种立地类型上 ,每种立地至少有 3个重复 ,林龄为 2 2~ 35年 ,样地面积 0 .0 4~ 0 .1hm2 ,样地林分为郁闭度均在 0 .7以上的纯林 ,株数不少于 80株 ,林分只采用过下层抚育伐。调查时记载立地因子 ,进行树干解析 ,采用样地内 5株优势木进行平均高计算。通过数量化 理论对影响红皮云杉的主导立地因子进行相关分析 ,筛选出主导立地因子 ,进行立地类型的划分。以理查德生长函数对各立地类型生长进行模拟 ,建立生长模型及有关参… 相似文献
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《Scandinavian Journal of Forest Research》2012,27(5):427-435
In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(3):206-217
The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(1):53-61
This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(1):15-27
The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions. 相似文献
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本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。 相似文献
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《Scandinavian Journal of Forest Research》2012,27(2):131-138
The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(5):472-479
Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken. 相似文献
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Srisuda Thippayarugs Banyong Toomsan Patma Vityakon Viriya Limpinuntana Aran Patanothai Georg Cadisch 《Agroforestry Systems》2008,72(2):137-148
In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic
or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts
(stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea
(Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content
as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest
N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized
to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea,
largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for
N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant
components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N
released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures
were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality
components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in
the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols.
Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest
age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its
components are mixed. 相似文献
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A. Rigueiro-Rodríguez M. R. Mosquera-Losada E. Gatica-Trabanini 《Agroforestry Systems》2000,48(3):245-256
The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste
disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization,
(2) milk sewage sludge at 40 kg N ha−1 target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two
pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha−1. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha−1) + Trifolium repens L. group Ladino (4 kg ha−1) + Trifolium pratense L. var. Marino (1 kg ha−1); (2) Lolium perenne L. var. Tove (25 kg ha−1) + Trifolium repens L. group Ladino (4 kg ha−1) + Trifolium pratense L. var. Marino (1 kg ha−1). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea
(Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m2, with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect
on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage
sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but
affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral
systems.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献