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1.
Hiromitsu Kisanuki Arisa Nakai Akiko Nadamoto Masako Wakino 《Journal of Forest Research》2009,14(6):342-348
We determined patterns of microsite suppression in dwarf bamboo Sasa nipponica when grazing deer were absent. This bamboo species is able to outcompete Hondo spruce (Picea jezoensis var. hondoensis) saplings under many environmental circumstances. We set up two 10 × 100 m plots inside a deer-proof fence within a subalpine
forest on Mt. Ohdaigahara, central Japan, and two similarly sized plots outside the fence. Within the plots, we surveyed microsites
where spruce saplings grew. We measured height and shoot elongation of all spruce saplings, and culm height and cover ratios
of dwarf bamboo growing around each spruce sapling. Spruce sapling density and average height were higher inside the deer-proof
fence than outside, as were bamboo height and cover. Thus, there was a negative effect of deer browsing on vegetation parameters
outside the fence and a suppression of the negative effect of bamboo on spruce sapling growth inside the fence. Spruce sapling
height was higher in tree-fall pits than in other microsites inside the fence, whereas both dwarf bamboo height and cover
were lower in pits and rocky sites than elsewhere. In soil and collar microsites, spruce sapling shoot growth was lower and
bamboo height and cover were higher than in pits and rocky sites. Inside the fence, dwarf bamboo cover was high, but pits
and rocks suppressed its growth, allowing spruce saplings to flourish. To restore heavily damaged spruce forests with advanced
saplings, it will be necessary to construct deer-proof fences and create and maintain microsites with pits and rocks. 相似文献
2.
The indirect consequence of sika deer (Cervus nippon) grazing on the regeneration of Picea jezoensis var. hondoensis through its effect on the small rodent population was assessed by evaluating seed predation by mice inside and outside the
deer-proof fence on Mt Ohdaigahara, central Japan. Following construction of the deer-proof fence, Sasa nipponica, which covers the forest floor and is the main forage of deer, grew thicker inside the fence due to the absence of deer grazing
than outside of the fence. Higher numbers of two species of woodmice (Apodemus speciosus and A. argenteus) were found inside the fence, possibly because the thick S. nipponica growth provides better cover. Inside the fence, more seeds of P. jezoensis var. hondoensis were eaten by the mice than outside the fence. These results suggest that the mouse populations inside the fence increased
due to changes in S. nipponica cover, which subsequently increased seed predation by the mice, possibly preventing regeneration of P. jezoensis var. hondoensis. 相似文献
3.
Habitat structure in Oku-Nikko, Japan, has been substantially modified by the overabundance of sika deer (Cervus nippon). A deer-proof fence (15.0 km and 900 ha) was constructed in 2001 to conserve vegetation. Although the understory inside the fence is dominated by Sasa nipponica (hereafter, Sasa), an important forage plant for deer, that outside the fence is dominated by Aster ageratoides leiophyllus (hereafter, Aster), an unpalatable plant to deer, and, partly, by bare floor. In this study, we examined the effects of deer on ground-dwelling insects and earthworms, the primary food resources of raccoon dogs (Nyctereutes procyonoides), and, thus, the bottom-up cascading effects of the herbivore on the omnivorous carnivore. Between July and September 2008, we examined the abundance of insects and earthworms by pitfall trapping and hand-sorting methods, respectively, both inside and outside the fence. The abundance of earthworms and insects (Scarabaeidae and Rhaphidophoridae) was higher on forest floors with Aster and/or bare floors outside the fence than on those with Sasa inside the fence. These results indicate that the increasing deer population in this area probably increased the number of these invertebrates outside the fence by modifying understory vegetation and/or depositing dung. Furthermore, the sighting rates of raccoon dogs obtained by spotlight counts were greater outside than inside the fence, suggesting that deer probably exert bottom-up cascading effects on raccoon dogs, at least during May to November, when the invertebrates are predominantly fed on by the omnivorous carnivore. 相似文献
4.
The effects of removing aboveground vegetation on survival and growth of Hondo spruce (Picea jezoensis var. hondoensis) saplings were examined in a dense dwarf bamboo (Sasa nipponica) field inside a deer-proof fence built in a degraded sub-alpine forest on Mt Ohdaigahara, central Japan. All bamboo culms
were removed within a radius of 1 m from each sapling in a plot of 0.6 ha (removal plot), whereas no culms were removed in
two control plots of 0.1 ha. We measured the height, crown depth, and main shoot elongation over 1 year for all spruce saplings,
culm height and cover ratios of dwarf bamboo growing around each spruce sapling, and the light levels above each sapling.
Removal of dwarf bamboo regulated the culm height and bamboo coverage until the following summer such that light conditions
improved. The mortality of saplings smaller than the average culm height was lower in the removal plot (0.89%) than in a control
plot (5.9%). After bamboo removal, sapling height growth was reduced with increasing bamboo cover in the previous year. Complete
removal of the aboveground portions of covering bamboo improved sapling survival while regulating elongation growth, possibly
because of the sudden increase in light intensity. Thus, controlling the extent of dwarf bamboo removal might be necessary
to facilitate the growth of spruce saplings to restore the forest. 相似文献
5.
《Forest Ecology and Management》2006,233(1):133-142
Carbon accounting, forest health monitoring and sustainable management of the subtropical dry forests of Puerto Rico and other Caribbean Islands require an accurate assessment of forest aboveground biomass (AGB) and stem volume. One means of improving assessment accuracy is the development of predictive equations derived from locally collected data. Forest inventory and analysis (FIA) measured tree diameter and height, and then destructively sampled 30 trees from 6 species at an upland deciduous dry forest site near Ponce, Puerto Rico. This data was used to develop best parsimonious equations fit with ordinary least squares procedures and additive models fit with nonlinear seemingly unrelated regressions that estimate subtropical dry forest leaf, woody, and total AGB for Bucida buceras and mixed dry forest species. We also fit equations for estimating inside and outside bark total and merchantable stem volume using both diameter at breast height (d.b.h.) and total height, and diameter at breast height alone for B. buceras and Bursera simaruba. Model fits for total and woody biomass were generally good, while leaf biomass showed more variation, possibly due to seasonal leaf loss at the time of sampling. While the distribution of total AGB into components appeared to remain relatively constant across diameter classes, AGB variability increased and B. simaruba and B. buceras allocated more carbon into branch biomass than the other species. When comparing our observed and predicted values to other published dry forest AGB equations, the equation developed in Mexico and recommended for areas with rainfall >900 mm/year gave estimates substantially lower than our observed values, while equations developed using dry forest data from forest in Australia, India and Mexico were lower than our observed values for trees with d.b.h. <25 cm and slightly higher for trees with d.b.h. >30 cm. Although our ability to accurately estimate merchantable stem volume and live tree AGB for subtropical dry forests in Puerto Rico and other Caribbean islands has been improved, much work remains to be done to sample a wider range of species and tree sizes. 相似文献
6.
Forest pasturing of free-roaming livestock is a common practice in many parts of the world, but knowledge on how it affects tree regeneration in boreal forests is lacking. We mapped tree density, livestock site use and accumulated damage to young trees of commercial interest(Norway spruce, Picea abies L. Karst.) on 56 clearcuts inside and outside a fenced forest area used for livestock pasturing in Ringsaker, Norway. Inside the fence 56±1.8% of spruce trees were damaged compared to 37±3.4% outside. Proportion of damaged spruce trees was positively related to cattle use of the clearcut, but not so for sheep. On the most intensively used clearcuts, four out of five trees were damaged. The density of deciduous trees was five times lower inside compared to outside of the fence(varying with plant species). While livestock grazing may reduce resource competition in favour of spruce, the current animal density clearly is impeding forest regeneration in the study area. 相似文献
7.
María E. Rodríguez Guillermo N. Doffo Teresa Cerrillo Virginia M. C. Luquez 《New Forests》2018,49(3):415-427
Climate change will increase the frequency of extreme rain events, causing more flooding episodes. Willows are usually planted in marginal lands like flood prone areas. For willow plantations developed from rootless cuttings, the establishment phase is crucial, because the cuttings are still developing a shoot and root system and have a higher vulnerability to stress. A flooding episode during this early period may have a negative effect upon plants. We analyzed the responses to flooding of eight willow genotypes, representing important species from the economic and ecological point of view (Salix alba, S. matsudana, S. amygdaloides and S. matsudana × S. nigra hybrids). The treatments started when the plants were 2 months old and lasted for 3 weeks. They were identified as: Control (watered to field capacity); F10 (plants submerged 10 cm above soil surface) and F50 (plants submerged 50 cm above soil surface). The F50 treatment showed a greater growth reduction than the F10 treatment in most clones, either measured in height, diameter or total biomass. Both flooding treatments reduced significantly the root-to-shoot ratio compared to control plants. The F50 treatment increased the leaf nitrogen content and specific leaf area in all genotypes. Both treatments changed plant and leaf traits in different ways according to the depth of the floodwater. These changes may have lasting effects on growth recovery in the post-flooding period. Willow clones with a fast initial growth will be the best option to minimize growth reduction in areas prone to experience flooding episodes. 相似文献
8.
9.
By influencing belowground processes, streamside vegetation affects soil processes important to surface water quality. We
conducted this study to compare root distributions and dynamics, and total soil respiration among six sites comprising an
agricultural buffer system: poplar (Populus × euroamericana‘ Eugenei), switchgrass, cool-season pasture grasses, corn (Zea
mays L.), and soybean (Glycine max (L.) Merr.). The dynamics of fine (0--2 mm) and small roots (2--5 mm) were assessed by
sequentially collecting 35 cm deep, 5.4 cm diameter cores from April through November. Coarse roots were described by excavating
1 × 1 × 2 m pits and collecting all roots in 20 cm depth increments. Root distributions within the soil profile were determined
by counting roots that intersected the walls of the excavated pits. Soil respiration was measured monthly from July to October
using the soda-lime technique. Over the sampling period, live fine-root biomass in the top 35 cm of soil averaged over 6 Mg
ha-1 for the cool-season grass, poplar, and switchgrass sites while root biomass in the crop fields was < 2.3 Mg ha-1 at its maximum. Roots of trees, cool-season grasses, and switchgrass extended to more than 1.5 m in depth, with switchgrass
roots being more widely distributed in deeper horizons. Root density was significantly greater under switchgrass and cool-season
grasses than under corn or soybean. Soil respiration rates, which ranged from 1.4--7.2 g C m-2 day-1, were up to twice as high under the poplar, switchgrass and cool-season grasses as in the cropped fields. Abundant fine roots,
deep rooting depths, and high soil respiration rates in the multispecies riparian buffer zones suggest that these buffer systems
added more organic matter to the soil profile, and therefore provided better conditions for nutrient sequestration within
the riparian buffers.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
10.
Temesgen Yadeta Elmar Veenendaal Karle Sykora Zewdu K. Tessema Addisu Asefa 《林业研究》2018,29(6):1601-1609
The spatial pattern and abundance of herbaceous vegetation in semi-arid savannas are dictated by a complex and dynamic interaction between trees and grasses. Scattered trees alter the composition and spatial distribution of herbaceous vegetation under their canopies. Therefore, we studied the effect of Vachellia tortilis on herbaceous vegetation composition, biomass and basal area, and soil nutrients on sites with varying grazing intensities in the central rift valley of Ethiopia. Data were collected on species composition, cover and biomass of herbs and grasses, and soil moisture and nutrient contents under light, medium, and heavy grazing pressures, both under the inside and outside of V. tortilis canopies. Species richness was similar in both locations but decreased with increased grazing. Only the overall biomass and herb cover were significantly greater under the canopy than outside, and overall biomass showed significant unchanging decline with increased grazing. However, vegetation cover was significantly greater on moderately grazed sites compared to low and heavily grazed sites. All soil variables were significantly higher under V. tortilis canopies than outside. Our findings suggest that V. tortilis has more effect on composition and diversity of herbaceous vegetation than on species richness, and that V. tortilis promotes the herbaceous layer biomass by reducing soil moisture loss and increasing soil fertility under the inside than outside the canopies. Therefore, we suggest that management practices should be directed on reducing pressure on V. tortilis by regulating grazing. Low to moderate grazing levels (i.e., a stocking rate less than 39.6 TLU ha?1 yr?1) seems to be tolerable to ensure sustainable conservation of the species in the study area in particular and in semi-arid savannas in general. 相似文献
11.
12.
川滇高山栎林是川西亚高山地区地带性的灌丛群落,具有重要的生态水文功能。本文在川西巴郎山东南坡沿海拔梯度(2 551、3 091、3 549 m),研究了川滇高山栎林表土层(0 15 cm)和亚表土层(15 30 cm)的土壤微生物量碳氮、有机碳(TOC)和氮素含量的分布特征及其相互关系。结果表明:海拔3 549 m和3 091 m处两土层土壤TOC及其储量、总氮(TN)、水解氮含量无显著性差异,其含量均显著高于海拔2 551 m处;海拔3 091 m处表土层与亚表土层的铵态氮(NH4+-N)含量显著比3 549 m的高,但与2 551 m处的NH4+-N含量差异不显著;在3个海拔梯度,土壤层硝态氮(NO3--N)含量差异不显著;3个海拔梯度的总无机氮含量在表土层差异不显著,而亚表土层无机氮含量在海拔3 091 m和3 549 m处差异显著;表土层微生物量碳含量变化与有机碳含量变化特征一致,亚表土层土壤微生物量碳含量在3个海拔梯度差异显著;表土层土壤微生物量氮含量在海拔3 091 m处最高,但3个海拔梯度的差异不显著,亚表土层土壤微生物量氮含量随海拔梯度降低而减少,但差异不显著。相关分析表明:水解氮、TOC、TN和土壤微生物量氮含量之间极显著相关(P<0.01);土壤微生物量碳与水解氮、TOC和TN显著正相关(P<0.05);pH值与水解氮、TOC和土壤微生物量氮显著正相关;NH4+-N与pH值极显著负相关。 相似文献
13.
14.
In order to identify the optimum cutting density for producing the highest number of plantable seedlings of poplar clones,
a split-plot randomized block design was used to establish four cutting densities in plots. Based on data on the survival,
leaf area, seedling height, caliper, and biomass of 1-year-old seedlings of clones Nanlin-95, Nanlin-895, Nanlin-1388 and
NL-80351, the growth characteristics and seedling quality under four cutting densities were analyzed. Results indicated that
the leaf area, stem and leaf biomass, and caliper of seedlings of all four poplar clones increased with the decrease in cutting
density. Leaf area index reached its highest level at the spacing of 40 cm×40 cm, while the aboveground biomass of the seedling
on an area basis increased as the cutting density increased. Seedling quality at low cutting density was higher than that
at closer cutting density. The quantity of first-grade seedlings (grade I) for clones Nanlin-95 and Nanlin-895 was achieved
at the spacing of 40 cm×50 cm; for NL-1388 and NL-80351, it was 50 cm×50 cm. According to the seedling quality and the number
of plantable seedlings produced, the suggested cutting density for these four poplar clones was 50,000 stems/hm2. 相似文献
15.
16.
Masaki Ando Akemi Itaya Shin-Ichi Yamamoto Ei'ichi Shibata 《Journal of Forest Research》2006,11(1):51-55
The long-term changes of the area of Sasa nipponica grassland, bark stripping damage to trees by sika deer, Cervus nippon, and sika deer densities on Mt. Ohdaigahara were assessed with aerial photographs, information from previous studies, and
field experiments. The grasslands expanded year after year. The expansion rate was highest from 1982 to 1992, and lowest from
1992 to 1997. Bark-stripping damage on coniferous trees was heavier than that on broadleaf trees in both the early 1980s and
1998. The deer density in the eastern part of the area had been high (14.4–64.3 km−2) from 1984 until 1998. We presume that rich growth of S. nipponica and heavy feeding pressure by sika deer over the long term caused expansion of S. nipponica grasslands by killing canopy trees by bark stripping and preventing forest regeneration. 相似文献
17.
《Scandinavian Journal of Forest Research》2012,27(1-4):307-316
The average stump and below‐ground biomass of pine was 1464 g/m2; 4% as fine roots (Ø<1 mm), 18% small roots (Ø=1–10 mm), 49% large roots (Ø>10 mm), and 29% stumps), which comprised 35% of the total biomass in the Scots pine stands. The average root length of pine was 728 m/m2: 71 % of this length was fine roots, 29% was small roots, and less than 1 % was large roots. Most of the fine pine roots (80%) were in the 0–10 cm peat layer. The root biomass of the field layer was 548 g/m2, which comprised 47 % of the total field layer biomass. Characteristic features of the root systems were: high below‐ground/above‐ground ratios, rather low amounts of root biomass, shallow rooting, and relatively thin roots. Hummocks tended to have less roots in the 0–10 cm layer and more roots in the 10–20 cm layer than the hollows. 相似文献
18.
Akio Inoue 《林业研究》2013,24(3):525-530
We investigated the culm form for one of the largest bamboo species, Phyllostachys pubescens Mazel ex Houz. in relation to the mechanical constraint principles, i.e., elastic, stress and geometric similarity. The fine-resolution analysis of the culm taper indicated that the culm for P. pubescens consisted of three or four segments with various forms, except for the butt swell. This implied that the taper of the whole culm for P. pubescens could be expressed by neither of these principles. The regression slope between culm height and diameter at breast height on the double logarithmic coordinates was 0.629, which was significantly different from the values predicted from these principles. In conclusion, none of these mechanical constraint principles can express the culm taper and height-diameter relationship, and there may be a need for a more complicated model to express the culm form for P. pubescens. 相似文献
19.
Modern alley cropping designs, with trees aligned in rows and adapted to operating farming machinery, have been suggested for Europe. This paper explores the potential for adoption of cork oak (Quercus suber L.) agroforestry in Portugal and estimates the potential carbon sequestration. Spatial modeling and Portuguese datasets were used to estimate target areas where cork oak could grow on farmland. Different implementation scenarios were then modeled for this area assuming a modern silvoarable agroforestry system (113 trees ha?1 thinned at year 20 for establishing 50 trees ha?1). The YieldSAFE process-based model was used to predict the biomass and carbon yield of cork oak under low and high soil water holding capacity levels. Approximately 353,000 ha are available in Portugal for new cork oak alley cropping. Assuming implementation rates between 10 % of the area with low soil water capacity (60 mm: 15 cm depth, coarse texture) and 70 % of the area with high soil water holding capacity (1,228 mm: 200 cm depth, very fine texture), then carbon sequestration could be 5 × 106 and 123 × 106 Mg CO2 respectively. Due to higher yields on more productive land, scenarios of limited implementation in high productivity locations can sequester similar amounts of carbon as wide implementation on low productivity land, suggesting that a priori land classification assessments can improve the targeting of land and financial incentives for carbon sequestration. 相似文献
20.
试验采用L16(45)正交试验设计对马山县古寨乡喀斯特丘陵坡地麻竹林进行尿素、钙镁磷肥、沸石3种肥料的施肥试验,研究不同施肥组合对单株或单位面积的地上生物量分配影响。结果表明:施肥对提高新竹地上生物量具有一定的促进作用,以施用尿素500 g+钙镁磷肥1 000 g+沸石5 000 g、钙镁磷肥4 000 g+沸石5 000 g效果显著,且极显著高于不施用的处理,但在低P、低Si、无N或无P或无Si等3种情况下,杆重比例均为较低。各处理以竹秆所占的比例最大,为61.0%～88.8%,其次是枝。各器官比例与肥料施用比例没有直接的关系。初步认为,单株或单位面积地上部分总生物量、杆重达到较高时,秆、枝、叶较适合比例为73%～74%、18%～19%、8%。杆重比例的高低与单株或单位面积杆重、地上部分总生物量的关系无规律性,而单株杆重是影响单位面积杆重、地上部分总生物量的主要因子,随着各处理单株杆重增加,单株或单位面积地上部分总生物量也增加。枝、叶所占比例无规律变化,但各处理中杆、枝比例表现出高杆低枝或低杆高枝的趋势。杆、枝和地上部分总生物量的增减与叶量比例的关系无规律性变化,叶片数量对单株或单位面积的竹杆、竹枝和地上部分总生物量影响不显著,这可能与麻竹生物学特性有关。认为留好母竹,合理施用肥料是提高喀斯特丘陵坡地麻竹产量的最佳途径。 相似文献