红松生长与温、湿度的相关分析

温度与湿度对红松生长的影响很大,观测结果表明,红松树高生长随温度的年变化而改变,4月中旬温度在10℃时,树高新枝开始生长,5月进入速生期,7月基本停止生长,生长期为80~90d左右,气温在12~20℃之间。昼夜的温差变化对红松的树高生长非常明显,白天的平均温度为17.5℃,夜间的平均温度为12.2℃,红松树高白天生长量为0.29cm,夜间树高生长量为0.53cm,夜间树高生长量是白天的1.8倍。相对湿度对红松树高生长影响的变化与温度日变化规律相同。     

草河口地区班克松引种试验效果分析

班克松引种到辽宁省本溪县草河口地区造林已达12a，通过对其生物量和生长量的调查结果表明，树高、胸径生长与当地乡土速生树种红松相差无几，且根系发达、生长稳定、无病虫害。说明班克松这一优良树种在草河口地区可以达到预期引种效果。     

岷江上游干旱河谷辐射松引种造林研究

经过连续14 a的辐射松(Pinus radiata D.Don)引种造林研究,结果表明(1)采用1.5 m×2.0 m造林密度,短册状或水平沟整地,采用石块、塑料薄膜覆盖,造林成活率达96%,保存率达90%.(2)抚育压青6 a的辐射松幼树树高生长量为对照的2.02倍,地径生长量为对照的2.19倍;每株幼树施20 g(N)+100g(P)施肥量的树高生长量比对照提高65.7 cm～120.2 cm,地径生长量比对照提高1.74 cm～3.83 cm;1/3修枝强度比对照树高生长量提高295.7 cm,地径生长量提高3.0 cm,1/4修枝强度比对照树高提高198.1 cm、地径生长量提高2.54 cm;(3)辐射松1 a中有2次高生长高峰期、3次径生长高峰期,高、径速生期在4～6龄年出现,幼林的根系、枝干、叶的生物量在5 a生时也急剧增加.     

泡桐苗期年生长参数的分析研究

对位于河南省通许县试验点的16个泡桐无性系进行苗期测定的基础上，研究分析其苗期生长规律及生长参灵敏，结果表明，泡桐苗期年生长符合S型生长曲线，16个无性系185株苗木年生长进程平均为；地径生长速生始期为6月12日，此时生长速度为0.033cm.d^-1，生长量达1.08cm；7月16日达到全年最大生长速度(0.049cm.d^-1)，皮时生长量达2.57cm，8月20日生长量达到4.05cm。速生期6月12日至8月20日，持续69d，全年生长量5.l3cm。苗高速生始期晚于地径，为7月8日，此时生长速度为0.049m.d^-1，生长量达0.86m；7月27日达到最大生长速度（0.073m.d^-1)，此时生长量达到2.04m;8月15日生长量达到3.22m，速生期7月8日至8月15日，持续37d，全年生长量为4.09m，地径与苗高生长量均与各自的速生持续期及最大生长速度有极显著的正相关关系。     

水曲柳个体生长节律及优良单株选择试验

对水曲柳个体树高生长节律进行了研究。结果表明:各个体生长期无明显差异,速生期均在5月中旬至6月下旬,速生期生长量占全年生长量的70%～80%;个体间树高当年生长量差异显著,其中134#、146#、121#高生长优势明显,全年高生长量分别为76.2 cm、73.9 cm和73.6 cm,分别是对照个体的194.4%、188.5%和187.8%。初步选择出134#、146#、121#为优良个体。     

麻栎在郴州石漠化地区的栽培试验

研究了不同造林树种在石漠化地区的生长情况和不同海拔高度及土壤母质类型下麻栎的生长情况,结果表明：在郴州石漠化地区,麻栎-柏木混交林中麻栎的树高生长量(210.87～216.87 cm)及地径生长量(22.57～28.80 mm)大于柏木的树高生长量(148.60～188.60 cm)及地径生长量(20.00～22.24 mm);同样,麻栎-光皮树混交林中麻栎的树高生长量(244.83～250.47 cm)及地径生长量(30.34～34.40 mm)也大于光皮树的树高生长量(180.80～235.60 cm)及地径生长量(20.49～29.10 mm),从总体上看麻栎的生长情况表现显著优于柏木及光皮树,而后二者是郴州石漠化地区复绿造林的常用树种,这也表明麻栎适合于郴州石漠化地区的造林推广。另外,栎的树高和地径生长量受到海拔高度和土壤母质类型等立地条件的显著影响,表现为海拔高度越高生长量越小、石灰岩优于砂砾岩优于花岗岩,而对地径生长量的影响会弱于对树高生长量的影响。     

红松不同分布亚区优树群体结实与生长性状分析

对露水河红松无性系种子园中不同分布亚区优树群体的结实和生长性状进行调查与分析,结果表明：在相同立地条件下,结实株率、种子平均产量以南亚区优树群体最高,其次为北亚区,中亚区最低;单株平均结实数、球果平均长度与宽度、单果平均重量、千粒重以南亚区优树最高,其次为中亚区,北亚区最低,与纬度呈现反比状态,而与温度和湿度呈正比。南亚区优树群体的平均树高生长量最大,为10.2 m,分别高出北亚区、中亚区及对照的29.11%、59.38%、92.82%。胸径平均生长量各分布亚区的优树群体之间差异不显著,但均分别高出对照24.87%、21.64%、18.41%。     

不同分布亚区红松优树无性系主要经济性状分析

为选择在草河口地区生长、结实表现最好的优树无性系,对红松自然分布区内3个亚区、12个产地、720个优树无性系的30年生树高、胸径、结实量进行调查分析,结果表明:在相同立地条件下,树高、材积差异显著,南亚区北亚区中亚区,3亚区均低于草河口无性系(对照);结实量差异显著,南亚区中亚区对照北亚区;胸径差异不显著。在草河口地区树高、材积生长以草河口无性系最高,结实量以马鞍山林场的无性系为最好。     

辽宁省班克松物候及生长规律观察初报

对辽宁省引种的班克松进行物候期观察和生长规律调查。结果表明，班克松在4月中旬叶芽膨大，5月中旬硕芽展叶，6月中下旬完全展叶。雌雄花开花时间基本相同，5月中下旬开花，6月末结束花期。班克松树高生长前2a生长较慢，2a后进入到速生期，6a后连年生长量达到最高峰，8a后连年生长量开始迅速下降。胸径生长从第4a进入速生期，第8a连年生长量达到最大，第10a生长量开始下降。     

辐射松、马尾松、长叶松与晚松人工林的生长规律比较研究

对九峰试验林场的辐射松、马尾松、长叶松及晚松人工林生长规律的研究结果表明 :长叶松生长最慢 ,而不宜大面积发展 ;辐射松、马尾松与晚松均表现较好 ,且辐射松与晚松材积生长速率高于马尾松 ,至 2 2a后 ,辐射松材积的生长速率将超过晚松 ;辐射松 4a时胸径连年生长量最大 ( 1 85cm) ,树高速生期为 1 2～ 1 6a,材积速生期为 1 4～ 1 7a,数量成熟龄在 40a之后 ;马尾松 4a时胸径连年生长量达最大 ( 1 30cm) ,1 3a树高连年生长量达最大 ( 3 5 0m) ,材积连年生长量 2 8a最高 ( 0 0 1 60 1m3) ,数量成熟龄为 35～ 40a ;晚松胸径连年生长量在第 3年达最大 ( 1 85cm) ,平均生长量 9a时达最大 ( 1 0 8cm) ,树高速生期为 3～ 8a ,材积速生期为4～ 1 5a ,数量成熟龄为 2 5a。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

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.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

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.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

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.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

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.     

CAD与建筑设计的关系

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。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

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.     

Risk Perception Among Non-industrial Private Forest Owners

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.     

Interactions in decomposition and N mineralization between tropical legume residue components

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.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

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.