基于SPOT-5影像的马尾松毛虫虫害遥感监测研究

马尾松毛虫是马尾松林的主要害虫,危害很大,实施有效监测是对其进行防治的关键。以福建沙县为研究区,以SPOT-5遥感影像为数据源,基于短波红外波段、红光波段和近红外波段等构造归一化植被指数等光谱特性指数,基于灰度共生矩阵法提取均值等影像纹理特征,引入坡度、坡向等地形及林木因子构建马尾松毛虫虫害遥感监测指标,通过岭回归分析建立虫情级数估测模型进而反演,进行虫害监测信息提取,并与单纯基于光谱特性指数指标的虫害信息提取方法进行比较。结果表明:1)综合考虑影像的光谱特性、纹理特征与地形及林木因子影响进行虫害监测,显著增强了虫害的光谱响应能力,相比于单纯基于光谱特性的虫害监测信息提取,其总精度提高了14.28%;2)这些为林业生产实践提供技术支撑与理论借鉴,同时也在一定程度上推动遥感监测森林病虫害的理论认识与信息提取方法。     

马尾松毛虫成灾之年造成马尾松活立木材积生长量的损失不容低估

一、马尾松毛虫成灾之年马尾松活立木材积生长量明显下降众所周知马尾松毛虫Dendrolimus Punctatus Walrer是我国松林的大害虫,不仅危害面积大,且分布广,几乎有马尾松分布的省区均有不同程度的发生,但每年马尾松毛虫猖獗成灾之年,人们可见松林针叶被吃光如同火烧状,严重被害枯死的植株,人们砍伐就易于统计损失量,而受灾未死的活立木,究竟影响材积生长量多少?就不易     

思茅松毛虫防治的试验

中方县现有马尾松林面积11103公顷,为我县的主要绿化用材树种。自20世纪90年代以来,我县对马尾松毛虫进行了综合治理,马尾松毛虫的发生危害得到了有效的控制。近几年来,思茅松毛虫在我县的局部松林呈块状分布,主要危害马尾松林,其食量比马尾松毛虫更大,局部发生区危害较重时出现了针叶稀疏、光干现象,林相从远处看就象被火烧过一样,严重影响树木的生长。为此,我们采用两种农药对其进行防治试验。     

飞机低容量喷雾防治马尾松毛虫

马尾松毛虫是危害松林最严重的历史性害虫。主要危害马尾松 ,猖獗时还可危害湿地松、火炬松、黑松、雪松等松林。马鞍山森林公园位于武汉市东南近郊 ,山林主要树种为马尾松 ,历年不同程度的遭到马尾松毛虫的侵袭。其幼虫食害松树针叶 ,受害严重的松林针叶常被吃光 ,仅留枝梗 ,状如火烧 ,枯黄一片 ,被人们称为不冒烟的森林火灾。 1995年森林公园开幕时 ,第一代马尾松毛虫大发生 ,凤凰亭台、鸽楼、路上、松树上都有许多幼虫爬行 ,树上的幼虫弹跳于游客身上 ,由于幼虫体被毒毛 ,人体暴露部位常引起皮炎、关节肿局部症状 ,少数人还有畏寒、低热…     

马尾松尺■生活及生活习性的初步观察和防治试验

一、分布及危害马尾松尺 (Abraxax sp)是马尾松林的一个主要害虫。以幼虫期进行危害,症状似松毛虫危害状,严重时可将大面积的针叶吃光。其危害盛期,正是马尾松抽生长时期,所以对林木生长影响极大,连年受害可造成林木死亡。     

四川马尾松林区主要松毛虫改称油松毛虫的研究

马尾松是四川主要用材树种之一,分布在四川盆地及其盆地边缘地带。历年各地马尾松林均在不同程度上遭到松毛虫的危害,大发生的年份,其受灾面积可达100万亩左右,松毛虫是我省林业上的大害虫。过去,主要根据松毛虫种类与寄主的相关性〔2〕、〔4〕,认为马尾松林区的松毛虫种类是马尾松毛虫(Dendrolimus punctatus Walker)。但近年在四川却发现油松毛虫(D.tabulaeformis Tsai et Liu)主要危害马尾松〔13〕。〔14〕,因而,对四川马尾忪林区松毛虫的种类及其分布,在1979—1980年开展了调查研究,现报告如下。     

平岗低丘马尾松林经营指数研究

本研究通过对不同树种，不同混交比及不同覆盖率的松林内马尾松毛虫发生危害情况的调查资料进行综合分析，提出了抑制马尾松毛虫灾害的松林经营最佳指数为０．２－０．４。     

不同程度马尾松毛虫危害对松林植被群落的影响

采用样点调查法对不同程度马尾松毛虫危害松林的植被群落进行了调查。结果表明:不同程度马尾松毛虫危害对松林林分密度的影响不显著,但对松树生长量有着不同程度的影响,中、重度危害可降低松树的高度和胸径(重度危害三年后高度、胸径分别下降0.34 m和1.8 cm),轻度危害则可促进松林的生长;马尾松毛虫危害可适度改变松林的郁闭度和地表植被的盖度(中、重度危害后三年盖度分别上升15%和20%),对林下植被的恢复与生长有一定的促进作用;松林植被物种多样性分析表明,中、重度马尾松毛虫危害可有效增加林地植被物种的多样性,轻度危害则对林地植被物种多样性影响不大。     

取食不同受害程度的马尾松对马尾松毛虫种群数量的影响

利用不同受害程度的马尾松Pinus massoniana针叶饲养马尾松毛虫Dendrolimus punctatus，研究其对马尾松毛虫生长发育的影响.结果表明：马尾松毛虫取食不同受害程度松针后，幼虫的取食量、排粪量、蛹重、对食物的消耗和利用指数、化蛹率、生殖力、发育历期和死亡率均有所不同，其中幼虫的取食量、排粪量、蛹重、对食物的消耗和利用指数、化蛹率和生殖力以取食未受害松树（针叶损失0）的最高，重度受害（针叶损失75%）次之，轻度受害（针叶损失25%）再次，中度危害（针叶损失50%）最低，而发育历期和死亡率则相反，由此可见马尾松毛虫取食不同受害程度的松针对其种群数量有明显的影响。     

马尾松用材林3—4代类型区松毛虫防治指标的研究

通过对3—4代类型区马尾松毛虫室内外取食及为害针叶量、松树针叶蓄积量和人工模拟虫害对松树材积生长影响进行测定、研究分析的基础上,提出了该类地区马尾松用材林松毛虫防治指标。试验表明,因虫灾引起松林失叶25％时,一般情况下不必防治;失叶50％以上时,要根据害虫数量、林分状况及天敌对害虫控制能力等进行综合评断。防治指标与松树年龄的幂回归关系为 y=1.4903·x~(1.1688)。     

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.