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1.
研究华北落叶松林、山杨-白桦林、华北落叶松-白桦林、油松-华北落叶松林、白桦林5种类型防护林的枯落物和土壤水文效应。研究方法为浸泡法和环刀法。结果表明：1)枯落物蓄积量范围为11.26～17.75 t/hm2,山杨-白桦林最大,油松-华北落叶松林次之,白桦林最小,华北落叶松林、油松-华北落叶松林未分解层蓄积量大于半分解层,山杨-白桦林、白桦林、华北落叶松-白桦林规律相反。2)枯落物最大持水量为31.27～51.75 t/hm2,有效拦蓄量为23.69～27.70 t/hm2,均表现为山杨-白桦林最大,华北落叶松林最小,持水量(率)、拦蓄量(率)半分解层均大于未分解层。枯落物持水量和持水率与浸泡时间分别呈对数函数和指数函数。3)土壤容重为1.18～1.23 g/cm3,总孔隙度为43.75%～58.47%。土壤有效持水量为64.71～131.09 t/hm2,山杨-白桦林最大,白桦林次之,华北落叶松林最小,土壤入渗速率与入渗时间呈幂函数关系。4) 5种林分水源涵养能力大小排序为山... 相似文献
2.
鄂尔多斯退耕还林6种典型配置模式凋落物持水特性研究 总被引：1，自引：0，他引：1
《内蒙古林业科技》2015,(3)
通过对鄂尔多斯地区退耕还林6种典型配置模式凋落物持水特性的研究,结果表明:凋落物的累积年限越长和植物群落的生长量越大,累积量越大,累积年限最长的油松群落凋落物达到11.2 t/hm2,生长量最大的杨树-沙打旺群落凋落物累积量为8.4 t/hm2;凋落物的分解程度越强其持水率越高,杨树-沙打旺群落半分解层凋落物持水率最高达到340.4%;凋落物的分解强度越强,在吸水初期吸水量越多,大部分凋落物在吸水中后期表现为分解强度大而吸水量少;凋落物对降雨的有效拦蓄与凋落物的累积量和最大持水率呈极显著的正相关关系,有效拦蓄量最高的杨树-沙打旺群落达到20.7 t/hm2,最低的柠条锦鸡儿-沙打旺群落仅为8.3 t/hm2。 相似文献
3.
通过对帽儿山白桦和山杨天然次生林凋落物产量、林地枯落物现存量及其周转时间进行研究,结果表明:(1)白桦林和山杨林的年凋落量分别为435g!m-2和464g!m-2,两种林型凋落物的主要组分均为叶,占60%以上,其次为枝和碎屑,繁殖器官最少;(2)白桦林总枯落物现存量为1 421g!m-2,林地枯落物、小枝、未分解层和半分解层现存量各占1/3;山杨林总枯落物现存量为1 647g!m-2,林地枯落物小枝、未分解层和半分解层现存量比例分别为25%、45%和30%;(3)白桦林小枝、叶、碎屑周转时间分别为17.4a、1.6a和8.1a;山杨林小枝、叶、碎屑周转时间分别为6.9a、12.5a和11.5a,白桦和山杨林总体周转时间接近,分别为3.3a和3.5a。 相似文献
4.
5.
采用野外调查和室内浸泡法对猫儿山水青冈(Fagus longipetiolata)天然林不同分解层凋落物的储量、持水量、持水率和吸水速率进行研究。结果表明,未分解层、半分解层和全分解层的干凋落物储量分别为1.02、1.07、2.28 t/hm2。不同分解层凋落物的持水量和吸水速率在整个浸泡试验过程中均表现为全分解层半分解层未分解层;持水率表现为半分解层未分解层全分解层。方程拟合结果表明,不同分解层的凋落物持水量、持水率与浸泡时间呈对数关系;凋落物吸水速率与浸泡时间呈幂指数关系。 相似文献
6.
氮沉降对凋落物分解的影响研究进展 总被引：6，自引：0，他引：6
过去几十年的人类活动增加了陆地生态系统的氮输入量,对凋落物分解的影响有促进、抑制和没有影响3种情况。凋落物的基质质量影响凋落物的分解,其中木质素、纤维素、酚类物质、N浓度、P浓度、C/N比、C/P比、木质素/N比具有重要作用。人类活动引起的全球变化,如CO2增加、温度上升和降水变化,影响了氮沉降的速率和凋落物分解。未来氮沉降对凋落物分解的研究热点包括加强氮沉降对热带与亚热带森林凋落物和阔叶树种凋落物分解影响的研究,氮沉降对凋落物分解影响研究的长期化,采用13C同位素研究凋落物分解,注重凋落物分解对氮沉降与大气CO2浓度升高、气候变暖、降水变化、紫外线辐射增强、P沉降交互作用响应的研究。 相似文献
7.
热带林的反射率平均占辐射量的17.4％,向大气的有效长波辐射约占13.7％,净辐射约占70％。蒸散值约占年降水量的36—57％,平均为43.6％。水量平衡各分量、土壤CO_2释放量、森林小气候特征都与干湿季节的变化有明显的关系。山地雨林的年凋落物量平均为7.7±1.2t/ha,半落叶季雨林为9.7±2.3t/ha。物质循环的研究表明,热带林的有机物归还量大、分解快,在较少人为干扰下元素的输出较少,多用于系统内的循环利用。 相似文献
8.
不同间伐抚育强度对华北落叶松人工林林下凋落物的影响研究 总被引：1，自引：0，他引：1
文章以塞罕坝地区华北落叶松人工林为研究对象,主要研究在不同间伐抚育强度下其林下凋落物的现存量和持水量的变化情况。试验选取立地条件和成林状况基本一致的林分进行研究,设置弱度、中度、强度3种不同程度的间伐抚育强度与未间伐抚育林分进行对比研究,研究结果发现:伐后林分凋落物现存量表现为未伐(6.747t/hm2)弱度(6.209t/hm2)中度(5.121t/hm2)强度(3.922t/hm2),各林分持水量表现为未伐弱度中度强度,依次是2.527t/hm2、2.218t/hm2、1.690t/hm2、1.251t/hm2,且均是半分解层大于未分解层,平均持水量与凋落物现存量表现趋势一致。 相似文献
9.
小兴安岭南坡4种林分类型枯落物水文特性研究 总被引：3，自引：0，他引：3
对小兴安岭南坡的红松林、落叶松人工林、杨树林和白桦林的枯落物储量、持水量、吸水速率等水文特征参数进行调查分析研究及其持水特性试验,结果表明,红松林下枯落物储量最大53.89 t/hm^2,其后依次为杨树林42.66 t/hm^2、落叶松人工林30.54 t/hm^2、白桦林最小20.03 t/hm^2。在这4种林分枯落物中,红松林的有效拦蓄量为最大,相当于14.56 mm的降雨。经数据分析拟合,得到林下枯落物未分解层和半分解层吸水速率与浸水时间之间存在显著的负指数相关性（R〉0.99）。 相似文献
10.
不同立地条件下华北落叶松叶凋落物的分解特性 总被引：1，自引：0，他引：1
采用凋落袋法,研究2种立地条件下不同林分密度华北落叶松人工林叶凋落物基质质量、分解速率的差异。结果表明:海拔与坡度是造成2种立地(地位级Ⅲ,Ⅳ)差异的主要因子,华北落叶松叶凋落物季节失质量率均表现出双峰曲线,且在秋季失质量率最高。2种立地条件下,叶凋落物半衰期分别为2.57,2.67年,完全分解分别需要11.09,11.24年。叶凋落物年平均失质量率、分解速率及初始无机养分含量均表现出立地Ⅲ高于立地Ⅳ。与立地Ⅳ相比,在立地Ⅲ下,C/N均值、木质素含量均值更有利于凋落物分解。经t检验分析,2种立地条件下叶凋落物初始无机养分含量之间并无显著差异性,而有机养分中木质素含量、有机碳含量之间差异显著(P<0.05)。相关分析表明:凋落物分解速率与全碳、C/N、凋落物层厚度呈极显著负相关,相关系数分别为-0.735,-0.569,-0.758。叶凋落物质量指标表明:在立地Ⅲ条件下,林分密度为1675株·hm-2最为有利于凋落物分解;在立地Ⅳ条件下,则以林分密度1300株·hm-2最为有利于叶凋落物分解。 相似文献
12.
《Forest Ecology and Management》2005,219(1):29-42
The influence of stand composition and age on forest floor chemical properties, nitrogen availability, and microbial activity was examined in mixed and pure stands of Douglas-fir (Pseudotsuga menziesii) and paper birch (Betula papyrifera). Decomposition of Douglas-fir and birch litter over two years as well as annual litter input was also measured. Mixed and pure stands of each species aged 10–25, 50–65 and >85 years old were selected in the Interior Cedar Hemlock (ICH) zone of southern interior British Columbia. Significantly more total N was mineralized in the forest floor of pure birch compare to that of pure Douglas-fir stands while forest floor of mixed species stands had intermediate N mineralization values. When sampling times were pooled forest floor N mineralization was lowest in the young stands compared to the older stands. Stand composition did not significantly affect litter decomposition were found in litter decomposition, microbial respiration and biomass. Stand age, however, did affect these parameters significantly. More birch litter mass was lost in young stands than in their older counterparts while the opposite trend was observed for fir litter. Generally, lower basal respiration, microbial biomass and Cmic/Corg was found in young compared to older stands. Concentrations and contents of forest floor total N and exchangeable K and Mg, and pH under pure birch were consistently higher compared to pure Douglas-fir. While forest floor total C, available P contents, exchangeable K and Mg concentrations were lowest in young stands, no differences were observed for total N and exchangeable Ca. All litter nutrient concentrations and contents were highest in pure birch stands. No clear trends could be discerned in litter nutrient concentration data among stand ages, although when converted to nutrient contents, there was a general increase with stand age. Both stand type and age had significant effects on forest floor properties and processes suggesting that stand age is another factor to evaluate when assessing the influence of forest composition on forest floor processes and chemistry. In terms of the effect of mixture, the data indicated that the maintenance of paper birch in mixed stands in these forest may have some effect on nutrient availability and status. 相似文献
13.
Zhongling Guo Qingkang Li Jinping Zheng Wande Liu Chunnan Fan Yuandan Ma Guirui Yu Shijie Han 《Frontiers of Forestry in China》2007,2(1):47-54
From 2001 to 2003, the litter decomposition dynamics of dominant tree species were conducted using a litterbag burying method
in the broadleaf-Korean pine forest, spruce-fir forest and Ermans birch forest, which represents three altitudinal belts in
Changbai Mountain, northeast China. The spatial and temporal dynamics of litter decomposition and the effects of litter properties
were examined. Furthermore, the decomposition trend of different species was simulated by the Olson model, and results showed
that annual mass loss rates increased over time, but was not significantly correlated. Leaf decomposition rates increased
after decomposing for 638 days (1.75 years), and the order of dry weight remaining rates of leaf litter for different species
is: Asian white birch (Betula platyphylla) (24.56%) < Amur linden (Tilia amurensis) (24.81%) < Korean pine (Pinus koraiensis) (38.48%) < spruce (Picea jezoensis var. microsperma) (41.15%) < Ermans birch (Betula ermanii) (41.53%) < fir (Abies nephrolepis) (42.62%). The dry weight remaining rates of twig litter was smaller than that of leaf litter, and followed the order of
Amur linden (44.98%) < fir (64.62%) < Korean pine (72.07%) < spruce (73.51%) < Asian white birch (77.37%) < Ermans birch (80.35%).
The simulation results by the Olson model showed that, in leaf, the 95%-decomposition rates ranged from 4.5 to 8.0 years,
and annual decomposition rate (k) followed the order of Amur linden (0.686) > Asian white birch (0.624) > Korean pine (0.441) > spruce (0.406) > fir (0.397)
> Ermans birch (0.385); in twig, it ranged from 7.8 to 29.3 years, and k follows the order: Amur linden (0.391) > fir (0.204) > Korean pine (0.176) > spruce (0.157) > Asian white birch (0.148) >
Ermans birch (0.102). In general, the differences of decomposition rate are evident between leaf and twig litter and among
species, and were higher in broad-leaved species compared with coniferous species at the same elevation, and decreased with
the ascending of elevation.
__________
Translated from Acta Ecologica Sinica, 2006, 26(4): 1,037–1,046 [译自: 生态学报] 相似文献
14.
Jie He Wanqin Yang Liya Xu Xiangyin Ni Han Li 《Scandinavian Journal of Forest Research》2016,31(4):355-367
Forest gap in alpine forests may redistribute the hydrothermal conditions in winter and growing season, which may affect the releases of copper and zinc in foliar litter during decomposition. However, the details of this process are largely unknown. Foliar litters of willow (Salix paraplesia), larch (Larix mastersiana), fir (Abies faxoniana), azalea (Rhododendron lapponicum), birch (Betula albosinensis) and cypress (Sabina saltuaria) were selected in an alpine forest of eastern Tibetan Plateau. The litterbags were placed on the forest floor from gap center, canopy gap edge and expanded gap edge to closed canopy. Zinc and copper contents were studied as litter decomposition proceeded. After one year of decomposition, zinc accumulated in all foliar litters regardless of gap positions, but copper accumulated in the litters of fir, azalea and cypress. Separately, copper was released from all foliar litters in winter, whereas zinc in litters of larch, azalea, birch and cypress was released in winter. Moreover, both copper and zinc accumulated during the growing season regardless of litter species. Nevertheless, higher accumulation rates were observed under closed canopy compared with other gap positions. These results suggest that forest gap slows the releases of copper and zinc in foliar litter during forest regeneration in these cold biomes. 相似文献
15.
SuccessionisthedynanucdeveloPInentofecosystemswhichcanbecharactetindbyenergyandndneralcyclings.Eachsuccessionstagehasitscharaceristicsofelementcycling.SomeschOlarshaveStatedbutbrieflawsofnutrienCyclinginsuccessionstagesI"3I.InthespaPer,thenutrientcyclingcharacterishcsofbirchsuccessionseriesinXiaokinganlingwerediscussed.SwrYAasAroarernoDSThestUdyareaislocatedinLiangshniNatUralReservesinthendddieofXiaox-ing'anlilg(l28"53,2o'rE,47olo'5O"N).Theclimat6belongstocontinentalmonsoonclimate,W… 相似文献
16.
以内蒙古根河林业局潮查林场境内的在20世纪80年代初主伐利用后形成的兴安落叶松过伐林为研究对象,利用兴安落叶松林8块标准地每木定位数据,分析林木分布格局和样方(5 m×5 m)林木株数对枯立木株数影响,探讨了林分大树和更新幼树位置与枯立木位置的关系,阐明了枯立木分布格局形成机制。结果表明:1)各树种枯立木比例,随树种组成成数增加而增大。枯立木主要在更新幼树阶段形成,径级分布集中在4径阶以下,其株数占总数的比例平均达82.2%。在更新幼树(含枯立木)中,生成枯立木的比例平均达8.8%。2)枯立木分布格局为聚集分布。林木分布格局、样方林木株数和更新株数与枯立木株数有显著正相关关系,林木分布格局对枯立木分布格局无显著影响。林木聚集度越大,形成枯立木的可能性越大,数量也就越多。3)枯立木位置与更新幼树和大树位置有显著相关关系。主要表现为落叶松和白桦相互关系。枯立木出现位置主要在大树和更新幼树集聚区域。大树对枯立木形成影响较更新幼树大,而且均以落叶松较白桦明显。白桦更新幼树对落叶松枯立木的形成,无显著影响。受影响的枯立木主要是枯立木株数中所占比例和树种组成成数较高的树种。影响枯立木位置的林木主要取决于其样方内位置和林木株数。 相似文献
17.
Analyses of land snails and habitat factors in acid beech forests were conducted in southern Germany (northern Bavaria). The
objectives were to study the effects of habitat characteristics on snail density and species richness. Habitat structures
were determined for 37 plots in one big forest. We found a significant relationship between the number of snail species and
individuals and the following set of habitat factors coverage of herbaceous layer, growing stock, mean diameter at breast
height of the three largest trees (DBHmax), stand age, total dead wood volume per ha, and advanced decomposed dead wood volume
per ha. We use maximally selected rank statistics to estimate cutpoints separating stands with low densities, from stands
with high snail densities. Here, we define cutpoints for a significant higher snail density at a stand age of 187 years, 57 m3/ha dead wood, 40 m3/ha advanced decomposed dead wood, 63 cm DBHmax and more than 1% herbaceous layer. For species richness, cutpoints are estimated
at 338 m3/ha stand volume, 170 years stand age, 50 m3/ha total dead wood amount, 15 m3/ha advanced decomposed dead wood and 56 cm DBHmax. The microhabitat analysis shows a higher pH value and a higher Calcium
content at the bottom of large snags and under large lying dead wood pieces in comparison to litter, upper mineral soil and
at the bottom of vital living trees. Snail species and individual density are significantly linked to these patterns of chemical
parameters. The identified cutpoints are a good base for ecological management decisions in forest management. 相似文献
18.
《Scandinavian Journal of Forest Research》2012,27(1-4):446-456
The dynamics of three major mineral nutrients (K, Ca, Mg) and six heavy metals (Fe, Mn, Zn, Cu, Pb and Cd) were studied in decomposing natural, unpolluted litter in two forest types: Scots pine needle litter in a pure Scots pine forest and oak‐hornbeam leaf litter in a mixed oak‐hornbeam stand. Of the mineral nutrients, only K in the oak‐hornbeam system showed a significant decrease in concentration during the course of litter decomposition. For Ca and Mg in both systems and for K in the Scots pine system no clear relation between concentration and accumulated litter‐mass loss was observed. On the other hand, for Fe, Zn, Pb and Cd at both sites, as well as for Mn in the oak‐hornbeam stand and Cu in the Scots pine stand highly significant positive relations were found between heavy metal concentrations and accumulated mass loss. A decrease in concentration was noted only in the case of Mn in the Scots pine system. No clear pattern was found for Cu in the oak‐hornbeam stand. Concentrations of heavy metals in the decomposing litter reached levels at or above those reported to retard decomposition in other studies. At the oak‐hornbeam stand increased also the absolute amounts of Fe, Zn, Pb and Cd. 相似文献
19.
Height–diameter equations for boreal tree species in Ontario using a mixed-effects modeling approach
Height–diameter relationships based on stand characteristics (trees/ha, basal area, and dominant stand height) were investigated for balsam fir, balsam poplar, black spruce, jack pine, red pine, trembling aspen, white birch, and white spruce using data from permanent growth study plots in northern Ontario, Canada. Approximately half the data were used to estimate model parameters with the rest used for model evaluation. Multiple Chapman–Richards functions with parameters expressed in terms of various stand characteristics were fit to determine the best models for predicting height. 相似文献
20.
杉木人工林间伐后林下植被生物量的研究 总被引：5，自引：0，他引：5
对杉木人工林间伐后林下植被生物量的变化进行测算分析,结果表明,间伐以后,由于林下空间环境因子的变化,植被生物量大量增加,为对照区的3.25倍其中灌木生物量增加273.5％,由对照区占林下植被总生物量的79.78％,提高到91.75％.且灌木种类增多,并尤以层外植物较多.其生物量占灌木生物量的50.25％;草本生物量增加32.49％;林下死地被物生物量达9100kg／hm2,比对照区增加92.80％。 相似文献