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1.
Atsushi Sakai Takahisa Hirayama Shigenori Oshioka Yasumasa Hirata 《Journal of Forest Research》2006,11(4):253-265
Large areas of previously clear-cut conifer plantations have been recently abandoned in Japan. We investigated the vegetation
in the clear-cut sites and examined the environmental factors affecting species composition of the vegetation. We set up 32
study sites, each composed of several study plots (5 × 5 m), ranging from 220 m to 1060 m a.s.l. Elevation and warmth index
(cumulated thermal quantity) were the primary factors affecting the species composition, with clear-cut areas showing a smaller
effect in the nonmetric multidimensional scaling (NMS) ordination. Two-way indicator species analysis (TWINSPAN) divided the
32 study sites into ten vegetation groups, clustering the sites by elevation or by postharvest disturbances (i.e., replanting
or browsing of Sika deer). Deciduous trees and shrubs were significant in the vegetation cover at higher elevations, while
they were less so in areas of high Sika deer populations. We also investigated the abundance of old-growth species, which
are expected to regenerate where the clear-cut site is abandoned. Evergreen Quercus and Castanopsis saplings were abundant at low elevations (<600 m), suggesting that they will successfully regenerate. The sapling densities
of Abies firma and Betula grossa were significantly large where a clear-cut site was adjacent to natural forest, which is expected to act as a seed source.
This implies that degraded deciduous forests may establish after clear-cutting at intermediate and high elevations (>600 m)
if the clear-cut site is distinct from seed sources. It is argued that the preservation of natural forests is critical for
the regeneration of old-growth species. 相似文献
2.
This study clarified the origin of Al in spring water and stream water by analyzing the size distribution of Al of ground
water, spring water, stream water, and soil extracts obtained by batch and column experiments using samples from a suburban
secondary forest on granite bedrock in Aichi Prefecture. The high concentration of dissolved Al (Al0.45; fraction through 0.45-μm filter) in water samples obtained from this study site was divided into completely dissolved and
small colloidal forms (<0.20 μm; Al0.20) and large colloidal forms (0.20–0.45 μm). More than 50% of dissolved Al (Al0.45) in spring water existed in large colloidal form. By comparing the size distribution and concentration of various elements
including Al in the samples from soil batch and column experiments, we suggest that the high concentration of Al in spring
water is caused by the release of Al from surface soils when ground water emerges as spring water. 相似文献
3.
孟加拉国丘陵地带桔园和灌木林地土壤物理性质的比较评价 总被引:1,自引:1,他引:0
Mohammad Shaheed Hossain Chowdhury Md. Abdul Halim Shampa Biswas S. M. Sirajul Haque Nur Muhammed Masao Koike 《林业研究》2007,18(3):245-248
The physical properties of soil on two hill slopes of 35% and 55% in orange orchard cultivated by the Mro tribe of Chittagong Hill Tracts (CHTs) were evaluated and compared with those of bushy hill forests. Soil samples were collected from three different depths (0-5 cm, 5-15 cm and 15-30 cm), digging three profiles in each land use for determining moisture content, organic matter content and particle density. Maximum water holding capacity, field capacity, dry and moist bulk density and porosity were determined only for the surface soils. Moisture content at all the soil depths was significantly higher (p≤ 0.05) in orange orchard than in forest on both the slopes. Orange orchard contained lower mean soil organic matter than forest on 55% slope, while it contained higher values on 35% slope compared to forest. The highest value of the above two properties was found at surface soil in both the land uses on both the slopes, decreasing with the increase of soil depth. On both the slopes maximum water holding capacity and porosity of surface soil and particle density at all soil depths were lower in orange orchard compared to those in forest. Field capacity values of surface soil did not show consistency in trend for the differences between the two land uses on both the slopes. Bulk density value of moist and dry surface soil was higher in orange orchard than in forest on both the hill slopes. 相似文献
4.
Experimental results were studied to determine the relationships between positioning precision of a differential global positioning
system (DGPS) and forest type, antenna height, and season, and to clarify the relationship between sampling number and the
convergence of positioning precision. Observation was carried out for 24 h. Mean circular area probability (CEP95) was 2.80 m for deciduous broadleaved trees, and 4.99 m for conifers. The mean CEP95 taken at 7 m height (3.14 m) was higher than that at 1 m height (3.92 m) at all sites. The mean CEP95 taken during the defoliation season (2.65 m) was slightly better than during the foliation season (2.96 m). There were significant
differences between forest types (P < 0.001) and antenna heights (P < 0.05). Positioning precision was not noticeably improved if the sampling number was around ten or less. A sampling number
of 100–1000 or more is required before substantial improvements can be expected. As long as high positioning precision is
not required, it is acceptable to use 2D & 3D modes and relatively few samples to take measurements.
Received: April 24, 2002 / Accepted: October 10, 2002
Correspondence to:I. Sawaguchi 相似文献
5.
Vegetation and weather explain variation in crown damage within a large mixed-severity wildfire 总被引:1,自引:0,他引:1
The 2002 Biscuit Fire burned through more than 200,000 ha of mixed-conifer/evergreen hardwood forests in southwestern Oregon and northwestern California. The size of the fire and the diversity of conditions through which it burned provided an opportunity to analyze relationships between crown damage and vegetation type, recent fire history, geology, topography, and regional weather conditions on the day of burning. We measured pre- and post-fire vegetation cover and crown damage on 761 digital aerial photo-plots (6.25 ha) within the unmanaged portion of the burn and used random forest and regression tree models to relate patterns of damage to a suite of 20 predictor variables. Ninety-eight percent of plots experienced some level of crown damage, but only 10% experienced complete crown damage. The median level of total crown damage was 74%; median damage to conifer crowns was 52%. The most important predictors of total crown damage were the percentage of pre-fire shrub-stratum vegetation cover and average daily temperature. The most important predictors of conifer damage were average daily temperature and “burn period,” an index of fire weather and fire suppression effort. The median level of damage was 32% within large conifer cover and 62% within small conifer cover. Open tree canopies with high levels of shrub-stratum cover were associated with the highest levels of tree crown damage, while closed canopy forests with high levels of large conifer cover were associated with the lowest levels of tree crown damage. Patterns of damage were similar within the area that burned previously in the 1987 Silver Fire and edaphically similar areas without a recent history of fire. Low-productivity sites on ultramafic soils had 92% median crown damage compared to 59% on non-ultramafic sites; the proportion of conifer cover damaged was also higher on ultramafic sites. We conclude that weather and vegetation conditions — not topography — were the primary determinants of Biscuit Fire crown damage. 相似文献
6.
Tree roots in a changing world 总被引:1,自引:0,他引:1
Globally, forests cover 4 billion hectares or 30% of the Earth's land surface, and 20%–40% of the forest biomass is made up
of roots. Roots play a key role for trees: they take up water and nutrients from the soil, store carbon (C) compounds, and
provide physical stabilization. Estimations from temperate forests of Central Europe reveal that C storage in trees accounts
for about 110 t C ha−1, of which 26 t C ha−1 is in coarse roots and 1.2 t C ha−1 is in fine roots. Compared with soil C, which is about 65 t C ha−1 (without roots), the contribution of the root C to the total belowground C pool is about 42%. Flux of C into soils by plant
litter (stemwood excluded) compared with the total soil C pool, however, is relatively small (4.4 t C ha−1 year−1) with the coarse and fine roots each contributing about 20%. Elevated CO2 concentrations and N depositions lead to increased plant biomass, including that of roots. Recent analysis in experiments
with elevated CO2 concentrations have shown increases of the forest net primary productivity by about 23%, and, in the case of poplars, an
increase of the standing root biomass by about 62%. The turnover of fine roots is also positively influenced by elevated CO2 concentrations and can be increased in poplars by 25%–45%. A recently established international platform for scientists working
on woody root processes, COST action E38, allows the exchange of information, ideas, and personnel, and it has the aim to
identify knowledge gaps and initiate future collaborations and research activities. 相似文献
7.
Atmospheric lead and cadmium deposition in bulk precipitation and throughfall was investigated at four forests in the Kanto
district, Japan, to assess the impact of human activities on the environmental health of forests. Annual lead and cadmium
depositions in bulk precipitation ranged from 8.9 to 25.7 g ha−1 year−1 and from 0.77 to 1.30 g ha−1 year−1, respectively. Lead and cadmium deposition increased in the summer at every forest due to large amounts of rainfall. At one
of the forests, the depositions were also high in the winter due to heavy snowfall. These depositions were similar to recent
depositions observed at other rural and urban sites in Japan and several forests in Europe and North America after 1990. These
results indicate that although anthropogenic lead and cadmium are deposited at these rates over wide areas, depositions are
still higher than in remote areas. 相似文献
8.
Wei Wang Hongjiang Zhang Meng Li Jinhua Cheng Bo Wang Weili Lu 《Frontiers of Forestry in China》2009,4(3):338-343
Spearman rank-correlation analysis and grey relational grade analysis were used to study infiltration characteristics of water
in different forest soils in the Simian mountains, Chongqing City. The results indicate that the soil bulk density, contents
of coarse sand, and porosity of macropores were significantly correlated with saturated hydraulic conductivity. Porosity of
macropores and contents of coarse sand were positively correlated with soil saturated hydraulic conductivity and soil bulk
density negatively. Based on the initial infiltration rate, the stable infiltration rate, time required for infiltration to
reach a stable state, and cumulative infiltration, all of which are crucial parameters determining soil infiltration capacity,
the results of grey relational grade analysis showed that the grey relational grades of the different forest soils were listed
from high to low as broad-leaved forest (0.8031) > Phyllostachys pubescens forest (0.7869) > mixed conifer-broadleaf forest (0.4454) > coniferous forest (0.4039). Broadleaf forest had the best ability
to be infiltrated among the four soils studied. The square roots of the coefficients of determination obtained from fitting
the Horton infiltration equation, simulated in our study of forest soils, were higher than 0.950.We conclude that soils of
broad-leaved forests were the best suited for infiltration processes of forestry in the Simian mountains.
__________
Translated from Journal of Soil and Water Conservation, 2008, 22(4): 95–99 [译自: 水土保持学报] 相似文献
9.
Vegetation recovery is a key measure to improve ecosystems in the Loess Plateau in China. To understand the evolution of soil
microorganisms in forest plantations in the hilly areas of the Loess Plateau, the soil microbial biomass, microbial respiration
and physical and chemical properties of the soil of Robinia pseudoacacia plantations were studied. In this study, eight forest soils of different age classes were used to study the evolution of
soil microbial biomass, while a farmland and a native forest community of Platycladus orientalis L. were chosen as controls. By measuring soil microbial biomass, metabolic quotient, and physical and chemical properties,
it can be concluded that soil quality was improved steadily after planting. Soil microbial biomass of C, N and P (SMBC, SMBN
and SMBP) increased significantly after 10 to 15 years of afforestation and vegetation recovery. A relatively stable state
of soil microbial biomass was maintained in near-mature or mature plantations. There was an increase of soil microbial biomass
appearing at the end of the mature stage. After 50 years of afforestation and vegetation recovery, compared with those in
farmland, the soil microbial biomass of C, N and P increased by 213%, 201% and 83% respectively, but only accounting for 51%,
55% and 61% of the increase in P. orientalis forest. Microbial soil respiration was enhanced in the early stages, and then weakened in the later stage after restoration,
which was different from the change of soil organic carbon. The metabolic quotient (qCO2) was significantly higher in the soils of the P. orientalis forest than that in farmland at the early restoration stage and then decreased rapidly. After 25 years of afforestation and
vegetation recovery, qCO2 in soils of the R. pseudoacacia forest was lower than that in the farmland soil, and reached a minimum after 50 years, which was close to that of the P. orientalis forest. A significant relationship was found among soil microbial biomass, qCO2 and physical and chemical properties and restoration duration. Therefore, we conclude that it is possible to artificially
improve the ecological environment and soil quality in the hilly area of the Loess Plateau; a long time, even more than 100
years, is needed to reach the climax of the present natural forest.
__________
Translated from Acta Ecologica Sinica, 2007, 27(3): 909–917 [译自: 生态学报] 相似文献
10.
Estimation of fire severity by use of Landsat TM images and its relevance to vegetation and topography in the 2000 Samcheok forest fire 总被引:1,自引:0,他引:1
Byungdoo Lee Seon Young Kim Joosang Chung Pil Sun Park 《Journal of Forest Research》2008,13(4):197-204
The severity of the 2000 Samcheok forest fire was classified by using Landsat TM images, and the effects of vegetation structures
and topographic conditions on fire severity were analyzed. The estimated normalized difference vegetation index differences
between the pre and post-fire Landsat TM images were used as the criteria in determining the levels of fire severity–low,
moderate, and extreme. According to the results from fire severity estimation, of the 10,600 ha forest stands, 28% was severely
damaged by crown fires, 38% was moderately damaged, and the remaining 34% was damaged slightly by surface fires. The overall
accuracy of the fire severity classification was 83% (Kappa coefficient = 0.76). The results of χ
2-tests showed that fire severity differed significantly with the vegetation and topographic conditions as follows. The coniferous
stands, compared with the mixed and broad-leaved, were more vulnerable to fire damage; the higher the slope of fire sites,
the greater the fire damage; the south was the most vulnerable aspect; fire severity of coniferous forest stands increased
with increasing elevation. However, in the study area it was found that fire severity of broad-leaved forest stands were negatively
related to the elevation of the corresponding fire sites and affected more by vegetation conditions rather than by topographic
conditions. 相似文献
11.
Precipitation of mineral phosphate is often recognized as a factor of limiting the availability of P in acidic soils of tropical
and subtropical forests. For this paper, we studied the extractable P pools and their transformation rates in soils of a tropical
evergreen forest at Xishuangbanna and a subtropical montane wet forest at the Ailao Mountains in order to understand the biogeochemical
processes regulating P availability in acidic soils. The two forests differ in forest humus layer; it is deep in the Ailao
forest while little is present in the Xishuangbanna forest. The extractable P pools by resin and sodium-bicarbonate decreased
when soil organic carbon content was reduced. The lowest levels of extractable P pools occurred in the surface (0–10 cm) mineral
soils of the Xishuangbanna forest. However, microbial P in the mineral soil of the Xishuangbanna forest was twice that in
the Ailao forest. Potential rates of microbial P immobilization were greater than those of organic P mineralization in mineral
soils for both forests. We suggest that microbial P immobilization plays an essential role in avoiding mineral P precipitation
and retaining available P of plant in tropical acidic soils, whereas both floor mass accumulation and microbial P immobilization
function benefit retaining plant available P in subtropical montane wet forests.
Translated from Acta Ecologica Sinica, 2006, 26(7): 2,294–2,300 [译自: 生态学报] 相似文献
12.
Ana Isabel Moreno-Calles Alejandro Casas Eduardo García-Frapolli Ignacio Torres-García 《Agroforestry Systems》2012,84(2):207-226
Agroforestry systems (AFS) derived from the cactus forest “chichipera” and cultivated with “milpa”, the traditional multi-crop
system of maize-beans-squash were studied in the Tehuacán Valley, Mexico. Plant management types practiced by people, role
of agricultural and forest resources in households’ subsistence, and consequences of changes in AFS were investigated through
ethnobotanical, ecological, and economic approaches. People maintain in this AFS 122 plant species that provide useful products
for 14 different purposes. Nearly 90% of useful plants are native to the region, representing 54% of all plant species recorded
in the chichipera forest. Management strategies were identified occurring on 63 species at landscape, parcel, and individual
plant levels. About 67% of managed plant species are left standing during clearance of vegetation; 35% are transplanted to
the parcels’ surrounding area, 32% receive particular protection, and 10 species from other areas are cultivated inside the
fields. During years of higher rainfall (~745 mm) AFS supply nearly 75% of the maize grain and 50% of the maize straw used
as fodder by households. AFS with intermediate vegetation cover have higher economic value than monocultures and forest. However,
plots with low forest cover and monocultures are progressively more common as consequence of socio-cultural processes. Local
traditional ecological knowledge and management techniques are crucial for managing resilience of these AFS. 相似文献
13.
本文于1981-1984年植物生长季节对四川卧龙自然保护区森林土壤水分状况,进行了定位研究,试验林地设置在1200-4300m海拔高度的不同生物气候带的森林类型下。选择的五处试验林地是:①常绿阔叶林下的山地黄壤;②次生落叶阔叶林下的山地棕壤;③针阔混交林下的山地暗棕壤;④暗针叶林下的山地棕色暗针叶林土;⑤高山草甸植被下的高山草甸土。试验结果阐明了试验林地土壤的蓄水性能,枯枝落叶层最大蓄36-313t/ha,森林土壤的渗透系数在1.54-5.33mm/min,试验林地生长季节森林土壤水分贮量,都在最佳含水量下限以下,试验林地森林土壤水分供给(生态湿度)顺序为:山地棕色暗针叶林土(重湿)>高山草甸土(重温)>山地棕壤(湿)>山地黄壤(较湿)>山地暗棕壤(较湿一潮)。 相似文献
14.
Naoki Murata Seiichi Ohta Atsushi Ishida Mamoru Kanzaki Chongrak Wachirinrat Taksin Artchawakom Hiroyuki Sase 《Journal of Forest Research》2009,14(4):212-220
In several areas in Northeast Thailand, evergreen and deciduous forests coexist under uniform terrain and climatic conditions.
We compared depth and physical properties of soils between evergreen and deciduous forests in the Sakaerat Environmental Research
Station to clarify what factor determines their distribution. The averaged soil depths were 79 ± 27 cm and 135 ± 58 cm in
the deciduous and evergreen forests, respectively. The soils in the deciduous forests were relatively coarser in soil texture
than those in the evergreen forests, particularly in the surface layers. The average available water capacity of the solum
was lower in the deciduous forest soils (78 mm) than in the evergreen forest soils (123 mm). Compared with the evapotranspiration
from the evergreen forest in the study area, the available water capacity of the evergreen forest soil was almost the same
as the water deficit during the dry season (November–February), while that of the deciduous forest soil was lower and insufficient
to maintain the evapotranspiration. These results suggest that the distribution of deciduous and evergreen forests in the
study area was associated with soil water availability, which mainly depends on soil depth. 相似文献
15.
Alexandre Badoux Michel Jeisy Hans Kienholz Peter Lüscher Rolf Weingartner Jonas Witzig Christoph Hegg 《European Journal of Forest Research》2006,125(1):27-41
The project “Lothar and Mountain Torrents” investigates the effect of storm-originated deforestation on the hydrology on three
scales within the Sperbelgraben catchment (Swiss Prealps). This article focuses on runoff measurements during a 3-year period
in two differently affected sub-catchments (≈2 ha) and on 2-year surface runoff measurements on smaller plots (50–110 m2). The link between these two scales and the results of irrigation experiments on 1 m2 areas are interpreted using a detailed map of forest site types describing soil and vegetation characteristics. Plot results
show that surface runoff is generated in two distinct ways. On the one hand, high amounts of saturation overland flow were
observed on wet areas of gleyic soils. On the other hand, hardly any surface runoff was measured on Cambisols, with the exception
of a short hydrophobic reaction at the beginning of storms occurring on areas with a thick organic litter layer (temporary
Hortonian overland flow). On the long term, the lightly damaged sub-catchment (SC1) yields less runoff than the highly damaged
one (SC2). This is confirmed when direct runoff volumes during flood events are considered. However, short and intensive showers
surprisingly lead to higher discharge peaks in SC1. This occurrence is explained by different geomorphologic characteristics
(mainly the channel density) and the spatial distribution of the moist to wet forest site types. Effects of deforestation
and local soil compaction due to forest clearing remain small on both plot and sub-catchment scale. 相似文献
16.
Cronan CS 《Tree physiology》1991,8(3):227-237
The surface adsorption characteristics of red spruce (Picea rubens) roots were examined as a function of changes in external acidity and cation concentrations. Root cation exchange capacity varied significantly with changes in pH, increasing from 110 micromol(c) g(-1) at pH 3.5 to 155 micromol(c) g(-1) at pH 4.5, and reaching 250 micromol(c) g(-1) at pH 7.0. In general, Al adsorption by spruce roots was much greater than either Ca or Mg adsorption under the same initial conditions. However, root affinity for the divalent cations was proportionately much more sensitive to pH changes than was root affinity for Al. The fractions of adsorbed Ca and Mg increased by 50 to 100% as pH increased from 3.5 to 4.5, whereas the fraction of adsorbed Al remained relatively constant at both initial pH conditions. Competition experiments at pH 3.5 and 4.5 indicated that Al adsorption was strongly favored over Ca adsorption, except at low Al concentrations (~10 micromol l(-1)), high solution Ca(2+)/Al(3+) ion activity ratios (> 1.5 to 5.0), and at the higher pH. These results suggest that cell wall exchange sites in red spruce roots will tend to become progressively saturated with Al under the prevailing conditions of many acidic forest soils. To the extent that root adsorbed Al interferes with the active uptake of Ca and Mg, this process of competitive cation adsorption can contribute to impaired mineral nutrition in the spruce forest community. 相似文献
17.
Vegetation structure of forest edges and type of adjacent field can affect seed and seedling survival patterns of tree species.
We investigated acorn removal and seedling survival of Quercus germana and Q. xalapensis in relation to woody plant density across old field-forest gradients with soft and abrupt edges. Experiments were established
along four parallel bands located at 40–50 m in the forest, forest and field edges (0–10 m to each side of the border), and
20–30 m in the old field. Within each band, woody plant and acorn density was measured, and four points for acorn and seedling
removal experiments were randomly positioned. In each position, 20 acorns or four seedlings were placed. Survival was monitored
during one month. In abrupt edges, acorn density was higher along edges than in forest interior. Also, higher acorn removal
and seedling mortality were observed in the adjacent old-field whereas acorn and seedling survival was the highest at the
edges. Acorn and seedling survival was positively correlated to woody vegetation density. As the vegetation density of field
and forest edges grows, abrupt edges develop into soft edges, and they become more hospitable to oak recruitment and then
to forest cover expansion. 相似文献
18.
Soil moisture content (0–90 cm depth) and nitrate-nitrogen (NO3-N) concentrations in soil solution (90 cm depth) were monitored after gap formation (diameter 15–18 m) in three Danish beech-dominated forests on nutrient-rich till soils. NO3-N drainage losses were estimated by the water balance model WATBAL for one of the sites. Two forests were non-intervention forests (semi-natural and unmanaged), the third was subject to nature-based management. The study was intended to assess the range of effects of gap formation in forests of low management intensity. In the unmanaged and the nature-based managed forest, soil solution was collected for 5 years and soil moisture measured in the fourth year after gap formation. Average NO3-N concentrations were significantly higher in the gaps (9.9 and 8.1 mg NO3-N l−1, respectively) than under closed canopy (0.2 mg l−1). In the semi-natural forest, measurements were carried out up to 29 months after gap formation. Average NO3-N concentrations in the gap were 19.3 mg NO3-N l−1. Gap formation alone did not account for this high level, as concentrations were high also under closed canopy (average 12.4 mg NO3-N l−1). However, the gap had significantly higher N concentrations when trees were in full leaf, and NO3-N drainage losses were significantly increased in the gap. No losses occurred under closed canopy in growing seasons. Soil moisture was close to field capacity in all three gaps, but decreased under closed canopy in growing seasons. In the semi-natural forest, advanced regeneration and lateral closure of the gap affected soil moisture levels in the gap in the last year of the study. 相似文献
19.
《Forest Ecology and Management》1998,112(3):245-252
Effects of a land use change from grassland to coniferous plantation forestry (Pseudotsuga menzieii [Douglas fir]; Pinus radiata [radiata pine]) on soil acidity and organic matter were assessed at two sites in New Zealand. The sites differed with respect to soils, climate, vegetation cover and type, relative maturity and management of the forest stands. Results obtained at the different sites were, therefore, not directly comparable, although they represented a comparison of a similar change in land use and some overall trends were evident. The change from grassland to conifers decreased levels of organic carbon, total nitrogen and exchangeable cations and increased exchangeable acidity in the upper 20–30 cm of soil. Exchangeable aluminium and exchangeable acidity were more sensitive measures of the effects of afforestation on soil acidity than pH. 相似文献
20.
Microclimate in agroforestry systems in central Amazonia: does canopy closure matter to soil organisms? 总被引:7,自引:0,他引:7
Christopher Martius Hubert Höfer Marcos V.B. Garcia Jörg Römbke Bernhard Förster Werner Hanagarth 《Agroforestry Systems》2004,60(3):291-304
Microclimate was recorded and soil organisms were collected 1997-1999 in ecosystem stands of contrasting structure in central
Amazonia (a primary forest, a 12-year secondary forest, two different agroforestry systems, a rubber tree (Hevea brasiliensis) plantation, and a peach palm (Bactris gasipaes) monoculture with a densely closed canopy). The aim was to look at the effects of canopy closure on microclimate and soil
organisms. Monthly maxima temperature, average air and soil temperatures, and saturation deficit were highest in September
1997, and total annual rainfall in 1997 was 12-28% lower than in the other study years. The monthly average litter temperatures
were consistently 2-4 °C higher in the plantation sites than in the rainforest and the secondary forest, and temperatures
on single days (not the monthly averages) in the plantations were up to 10 °C higher than in the primary forest. The highest
average litter and soil temperatures and the highest temperature maxima were recorded in the agroforestry plantations. Canopy
closure strongly determined the litter temperatures in the sites. Soil macrofauna biomass was also strongly correlated to
canopy closure (linear regression, P = 0.05). We conclude that a well developed canopy effectively protects the soil macrofauna
from high temperature variation and drought stress. Therefore, optimizing these agroforestry systems for canopy closure may
contribute to a better management of the beneficial soil decomposer community.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献