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以绥宁县堡子岭林场无间伐、间伐强度20%和50%的杉木人工林为研究对象,对其0～110 cm土层的土壤含水量进行观测研究。结果表明:间伐对杉木人工林土壤水分有明显的影响;浅层土壤(0～15、15～30cm)水分的变化均表现为随间伐强度的增加土壤含水量降低;间伐降低土壤含水量的趋势从30～45 cm土壤层开始改变,且水分动态变化程度与间伐强度正相关;间伐对0～110 cm的平均土壤含水量的影响表现为间伐强度20%无间伐间伐强度50%。合理的间伐强度能够有效调节土壤水源涵养能力,为科学协调林水关系提供理论依据。 相似文献
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开展幼林油茶不同液态施肥方式下的土壤理化性质研究。初步结果表明：①采用淋灌+100%施肥量和滴灌+60%施肥量的施肥方式均能有效提高油茶幼林林地土壤的pH值,且淋灌+100%施肥量效果显著;两种处理方式下林地表层土壤的pH值分别比滴灌不施肥高0.57和0.16;而深层土壤pH值分别比滴灌不施肥高0.41和0.39。②滴灌+60%施肥量能显著改善油茶林地的土壤含水量,且林地表层、深层土壤含水量较滴灌不施肥表层、深层土壤的含水量分别提高1.10%和1.18%。③淋灌+100%施肥量和滴灌+60%施肥量的施肥方式均能显著降低林地土壤容重和全N、全P含量,且滴灌+60%施肥量的效果优于淋灌+100%施肥量;两种措施的表层土壤容重较滴灌不施肥方式分别降低0.03 g/cm3和0.04 g/cm3;而深层土壤容重则分别降低0.04 g/cm3和0.06 g/cm3。④滴灌+60%施肥量能显著提高油茶幼林地土壤孔隙度与速效N、速效P和速效K,表层和深层土壤孔隙度则分别提高4.31%和5.00%,深层土壤中速效N、速效P和速效K增幅分别达到42.8%、88.9%和19.7%。水肥一体化的施肥方式能显著改善油茶幼林林地土壤的理化性质。 相似文献
3.
晋西北不同植被类型土壤水分空间分异 总被引：1，自引：0，他引：1
采用土钻法对晋西北朔州地区杨树林、柳树林、草地3种植被类型0~600 cm土层土壤水分动态进行研究。结果表明:土壤平均含水量表现为草地杨树林地柳树林地。草地土壤平均含水量比杨树林地高1.25%,比柳树林地高1.9%。随着土壤深度的增加,土壤含水量先减小后上下波动,然后趋于稳定。0~100cm土层范围内,土壤水分变异系数大小为草地柳树林地杨树林地;在200~300 cm、400~500 cm土层范围内,变异系数表现为柳树林地草地杨树林地;300~400 cm、500~600 cm土层范围内,变异系数大小为柳树林地杨树林地草地。越靠近表层,土壤干化现象越严重,柳树林地干化现象最明显,含水量变化最剧烈,杨树林地次之,草地最稳定。 相似文献
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《林业科学研究》2021,34(3)
[目的]探究不同间伐强度对柚木人工林土壤理化性质、酶活性及林木生长的影响,为柚木大径材高效培育和林地可持续经营提供理论依据。[方法]以15年生柚木纯林为研究对象,设置轻度、中度、重度间伐和对照4个处理。间伐3.5 a后,测定柚木生长量、土壤理化性质和酶活性等指标,分析不同间伐强度处理下各指标的差异。采用冗余分析法(RDA)分析柚木生长指标及土壤酶活性与土壤理化性质指标之间的关系。[结果]间伐对土壤理化性质及酶活性的影响主要表现在0～20 cm土层,间伐提高了土壤含水率,降低了表层土壤pH值;土壤有机质、碱解氮的含量随间伐强度的增大而增加,中度、重度间伐林分0～20 cm土层有机质含量比对照显著提高了18.2%和19.0%,碱解氮含量显著增加了15.7%和16.6%;间伐后土壤全氮和交换性钙含量也均增加。间伐显著增强了0～20 cm土层的蔗糖酶活性,而脲酶、酸性磷酸酶和过氧化氢酶活性变化无显著差异。柚木林分的平均胸径和单株材积随间伐强度的增大而增加,林分断面积和蓄积也均高于对照;重度间伐处理的林分各生长指标年均增量最大,并显著高于对照,平均单株材积和蓄积增量分别提高了80.0%和90.2%。土壤有机质、有效磷含量与柚木各生长指标呈正相关,田间持水量、土壤密度及总孔隙度是影响土壤酶活性的主要环境因子。[结论]间伐改善了土壤养分和水分状况,促进了柚木生长,林地生产力得到明显提高。间伐提高了与N、P循环相关酶的活性,显著增强了与C循环相关的蔗糖酶活性。对15年生柚木人工林进行间伐,适宜的间伐强度为40%～45%。 相似文献
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以华北落叶松人工林为研究对象,主要研究分析了不同间伐抚育强度下华北落叶松人工林林下土壤层的物理性质变化情况。选取指标主要包括土壤容重、土壤饱和含水量、土壤田间持水量以及土壤总孔隙度。研究结果表明：随着间伐强度的加大,林下土壤容重持续下降,其中0-10cm处的土壤容重相比未伐林分分别下降3．2％、5．2％、5．7％;lO-20cm处分别下降1．6％、1．6％、3．9％;土壤饱和含水量、土壤田间持水量、土壤总孑L隙度等指标也随间伐强度的增大而增加。对研究结果采用方差分析的方法进行显著性检验,结果表明：不同强度的间伐抚育对落叶松林土壤层的饱和含水量、田间持水量变化影响显著,对土壤容重和土壤总孑L隙度的变化影响不显著。 相似文献
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采集东北地区落叶松人工林、皆伐迹地和农田不同深度土壤进行分析,以便确定森林皆伐、农田化过程中土壤碳及肥力变化及其垂直剖面差异。结果表明:1)4个地点林地0~20 cm土层有机碳储量平均为93.0 t·hm-2,显著高于农田57%和皆伐地24%,而深层(20~80 cm)农田土壤有碳储量均值大多高于林地和皆伐迹地(P<0.05),但是后二者差异大多不显著;无机碳较有机碳低3个数量级,且与有机碳变化趋势相反,但对土壤碳收支影响较小。2)农田0~20 cm土壤全氮和碱解氮储量分别较林地低52%和65%(P<0.05),较皆伐迹地低30%和86%(P<0.05),但深层呈农田高于林地与皆伐迹地的趋势;农田0~20 cm土壤全钾储量高于林地39%(P<0.05),深层差异呈变小趋势;不同土层及不同处理方式之间土壤全磷储量均未产生显著变化。3)农田0~20 cm土壤密度显著高于林地(27%)(P<0.05)和皆伐迹地(15%)(P<0.05),但是深层差异不显著;不同土层林地、皆伐迹地和农田土壤pH值和电导率差异均未达到显著水平(P>0.05)。综合来看,不同处理对土壤的影响表层大于深层且差异明显,多数指标在农田、林地、皆伐迹地间变化趋势表层与深层不同甚至相反。 相似文献
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间伐对重阳木人工林土壤微生物量碳氮和酶活性影响 总被引：1，自引：0，他引：1
以太仓市20年生重阳木人工林为研究对象,研究了间伐4a后的重阳木人工林土壤微生物量碳氮含量以及土壤脱氢酶、过氧化氢酶、脲酶、碱性磷酸酶和蔗糖酶活性的变化.结果表明:间伐显著降低了土壤pH值、表层土(0～10 cm)C/N、亚表层土(10 ～20 cm)可溶性碳含量,增大了亚表层土壤微生物量碳含量和微生物量碳占总碳的比例,对微生物量氮无显著改变;间伐显著减小了过氧化氢酶活性,增大了亚表层脱氢酶活性,消除了蔗糖酶活性在不同土层之间的显著差异. 相似文献
10.
为了揭示间伐对人工林土壤养分的影响,以日本落叶松人工林为研究对象,分析了间伐对土壤物理与化学性质的影响。结果表明:间伐对土壤物理性质影响不显著,间伐增加了不同土层土壤pH值和有效磷含量,强度间伐提高了表层土壤的全碳和全氮含量,而对亚表层全碳和全氮无显著影响。 相似文献
11.
In Japan, selective thinning is a common thinning method, though line thinning receives much attention because of its economic merits. In this study, we examined effects of the two thinning methods on bird communities in Todo fir (Abies sachalinensis) plantations in Hokkaido, Japan. We surveyed bird species in forests under four different management types — unthinned, selectively thinned, line-thinned plantation, and naturally regenerated forest (here after referred to as natural forest) stands — using a line-transect method. We also investigated vegetation structure (canopy tree and understory) of these stands. Bird species richness did not differ between natural forests and plantations, while bird total abundance was greater in plantations than in natural forests. Bird species richness and total abundance were comparable among the three management types for plantations. Abundances of 10 bird species were different among the four management types, and five species were more abundant in line-thinned plantations. However, two species were more abundant in selectively thinned stands than in line-thinned stands, and they frequently appeared in natural forests. There were no distinct differences in vegetation structure among the management types for plantations. Our results suggest that line thinning could be beneficial for some bird species in plantations. 相似文献
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We studied the effects of line thinning on stand structure, microclimate and understory species diversity of two Cryptomeria japonica D. Don plantations in south-central Japan. In each of two study sites we compared stand structure between the thinned stand
and an adjacent unthinned stand and found that line thinning increased the growth rate of residual trees such that stand basal
area may recover within 10 years after thinning. In the thinned stand, more open canopy conditions resulted in higher maximum
temperatures on the forest floor during the early growing season than in the unthinned stand. The thinned stand had greater
understory plant species richness and biomass than the unthinned stand. This study suggested that line thinning could potentially
enhance biodiversity while simultaneously increasing tree-growth rates in overstocked Cryptomeria japonica plantations. 相似文献
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Effects of thinning intensity on species diversity and timber production in a conifer (Cryptomeria japonica) plantation in Japan 总被引：1，自引：0，他引：1
Kenji Seiwa Yukino Eto Masahiro Hishita Kazuhiko Masaka 《Journal of Forest Research》2012,17(6):468-478
In conifer plantations, enhancement of species diversity has become an important management goal. Although thinning is a useful method to enhance diversity, determining optimum thinning intensities may be rather complicated because of potential trade-offs among a broad array of management goals (e.g., recovery of biodiversity, increasing individual tree sizes, increasing net primary production, saving management costs). To evaluate the optimum thinning intensity by analyzing these relationships, we conducted a thinning experiment with three different thinning intensities—unthinned, 33% thinned, and 67% thinned—in a Cryptomeria japonica plantation in 2003, and investigated the number, diameter at breast height (DBH), and diversity of hardwoods (height?>?1.5?m) in 2008, and the growth of conifers over five?years. In hardwoods, the number of individuals, number of species, mean DBH, and total basal area were greatest in the 67% thinned treatment, irrespective of successional status. However, Shannon’s diversity index did not differ among the three treatments due to a disproportionate increase with thinning intensity in the abundance of a mid-successional species, Cornus controversa. Diameter growth of conifers was also highest in the 67% thinned and lowest in the unthinned treatment, whereas the reverse was true for stand volume increment. These results suggest that intensive thinning is a reliable method to convert conifer plantations into conifer–hardwood mixed forests at canopy level much more quickly and consistently than weak thinning, although primary production is to some extent reduced. If forest managers prefer sustainable timber production of conifers rather than full recovery of diversity, weak thinning may be suitable. 相似文献
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LIU Zu-gen ZHU Jiao-jun HU Li-le WANG He-xin MAO Zhi-hong LI Xiu-fen ZHANG Li-jun 《林业研究》2005,16(3):193-199
In order to understand the effects of thinning on microsite conditions and natural regeneration in the larch plantation, thinning experiment was conducted in a 40-year-old Larix olgensis plantation in Qingyuan County in eastern Liaoning Province, China in 2003-2004 Five thinning treatments （0%, 10.2%, 19.8%, 29.7% and 40.3% thinned） were designed on the same site. After thinning, canopy openness and the microsite conditions such as photosynthetic photon flux density （PPFD）, soil moisture content, and soil temperature were measured in one growing season. Meanwhile, the investigation of natural regeneration was conducted at the end of the growing season. The results showed that the canopy openness increased with the increase of thinning intensities. PPFD and soil temperature and soil moisture content in different soil layers were positively relative with canopy openness after thinning. The richness of regenerating tree species did not significantly increase （p=0.30） after one growing season since thinning, but the regeneration density and frequency of tree species increased significantly （p〈0.05）. In addition, the number of regenerating tree species increased, and the increment was correlated with the characteristics of iudividual tree species. The increasing percentage of regenerating seedlings of the shade-intolerant tree species was more than that of shade-tolerant tree species. Among the investigated regeneration species, the biggest response of seedling emergency to the canopy openness was Phellodendron amurense. This paper confirmed the following conclusions： after thinning, the variety of regenerating tree species was correlative with the characteristics of regenerating tree species, and the distribution of unthinned trees and the site conditions in the investigated larch plantation were the additional factors influencing, the regeneration. 相似文献
16.
A. Hirata T. SakaiK. Takahashi T. SatoH. Tanouchi H. SugitaH. Tanaka 《Forest Ecology and Management》2011,262(7):1280-1288
There is an increasing need to restore natural hardwood forests in landscapes dominated by monocultural conifer plantations. A convenient restoration approach is to exploit natural regeneration processes. Natural regeneration, however, is affected by diverse interacting factors, for which better understanding is required, in order to optimize restoration programs. To identify optimal management practices for improving natural regeneration of hardwood trees in coniferous plantations, we examined the effects of multiple factors on the abundance of seedlings, small saplings and large saplings (height <0.3, 0.3-1.3 and ?1.3 m, respectively) of hardwood tree and shrub species in both line thinned (LT) and unthinned (UT) plantations of sugi (Cryptomeria japonica) and hardwood forests (HF) in central Japan. The effects of management practices (number of the times of weeding and cleaning, thinning method, years after thinning and forest age), environment (slope position, slope angle and canopy openness), and landscape conditions (distance from nearest hardwood forest, altitude and landuse before planting) on the number of hardwood individuals were examined by using the data obtained from the LT plantations. We also compared hardwood density between LT and UT plantations to examine the effect of line thinning. Finally, we examined species composition of LT plantations and HF to identify hardwood forest components in the thinned plantations. The effects on hardwood regeneration of environmental conditions, landscape factors and management practices applied in the plantations varied, depending on the size class and life form of the regenerating species. The abundance of large saplings of tall tree species was affected by several management factors, especially number of the times of weeding. Landscape conditions (distance from the nearest hardwood forest and altitude) affected the abundance of small saplings and seedlings of tall tree species, but not the other classes. Seedlings and small saplings of many tall tree species that contribute to hardwood forest canopies were less abundant in the LT plantations. The results show that numerous factors affect the establishment and abundance of naturally regenerating hardwood tree species, and suggest that successful establishment during early plantation stages can have long-lasting effects on natural regeneration of tall tree species. 相似文献
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采用EnviroSMART土壤水分定位监测系统于2008-05-14至2008-10-11及2009-05-05至2009-08-05对晋西黄土区刺槐人工林、油松人工林(水平条整地)、天然次生林0～150cm土层的土壤水分进行实时监测。以这些监测数据为基础,分析SWUF模型参数的敏感性,进行参数率定,验证SWUF模型在晋西黄土高原水土保持林地的适用性。结果表明:SWUF模型中的蒸发参数、产流参数、非饱和水流参数属于高度敏感性参数,使用SWUF时必须对这些参数进行率定;SWUF模型对刺槐人工林20～150cm各土层、油松人工林和次生林0～150cm各土层土壤水分动态模拟效果较好,模拟值与实测值相对误差在20%以内;SWUF适用于模拟油松人工林和天然次生林各土层每日土壤含水量,也能够比较充分地模拟3种林地不同深度土壤层土壤水分的日变化趋势,但在模拟耗水量大的刺槐林表层土壤水分方面还需要改进。 相似文献
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A small scale agroforestry study which was begun in 1952 was revisited in 1985 to evaluate the long-term influence of site preparation and grazing on tree growth and survival in a Douglas-fir (Pseudotsuga menziesii)-white oak (Quercus garryana)-sheep silvopastoral system. In 1952–1953, two-year-old Douglas-fir seedlings were planted at the rate of 2500 trees/ha under three levels of site preparation: (1) no treatment, (2) oak thinned by 50%, and (3) oak clearcut. From 1954 to 1960, yearling ewes grazed one-half of each of the three thinning treatments for 3–4 weeks each spring. The conifers have been undisturbed since grazing was discontinued in 1960. Survival of planted conifers averaged 64% in 1985 and did not vary among either site preparation or grazing treatments. From 1964 to 1985, trees on the thinned and clearcut plantations grew an average of 1060 and 990 cm in height, respectively, compared to 900 cm on the unthinned plantation. Diameter at breast height (dbh) averaged 3.8 and 5.6 cm greater on thinned or clearcut plantations, respectively, than on the unthinned control by 1985 (p < 0.05). Conifers on grazed plantations had increased height and dbh growth during the first 12 years of plantation life, averaging 63 cm taller (p < 0.10) and 0.7 cm greater in dbh (p < 0.05) than the ungrazed plots by 1964. By 1985 the difference in height (122 cm) and dbh (1.0 cm) between grazed and ungrazed plantations was not statistically significant. These data suggest that although site preparation can positively influence conifer growth, total clearfelling is no better than thinning oaks. Furthermore, proper grazing can increase height and dbh growth of the conifers during and immediately after the grazing years. 相似文献
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A small scale agroforestry study which was begun in 1952 was revisited in 1985 to evaluate the long-term influence of site
preparation and grazing on tree growth and survival in a Douglas-fir (Pseudotsuga menziesii)-white oak (Quercus garryana)-sheep silvopastoral system. In 1952–1953, two-year-old Douglas-fir seedlings were planted at the rate of 2500 trees/ha under
three levels of site preparation: (1) no treatment, (2) oak thinned by 50%, and (3) oak clearcut. From 1954 to 1960, yearling
ewes grazed one-half of each of the three thinning treatments for 3–4 weeks each spring. The conifers have been undisturbed
since grazing was discontinued in 1960. Survival of planted conifers averaged 64% in 1985 and did not vary among either site
preparation or grazing treatments. From 1964 to 1985, trees on the thinned and clearcut plantations grew an average of 1060
and 990 cm in height, respectively, compared to 900 cm on the unthinned plantation. Diameter at breast height (dbh) averaged
3.8 and 5.6 cm greater on thinned or clearcut plantations, respectively, than on the unthinned control by 1985 (p < 0.05).
Conifers on grazed plantations had increased height and dbh growth during the first 12 years of plantation life, averaging
63 cm taller (p < 0.10) and 0.7 cm greater in dbh (p < 0.05) than the ungrazed plots by 1964. By 1985 the difference in height
(122 cm) and dbh (1.0 cm) between grazed and ungrazed plantations was not statistically significant. These data suggest that
although site preparation can positively influence conifer growth, total clearfelling is no better than thinning oaks. Furthermore,
proper grazing can increase height and dbh growth of the conifers during and immediately after the grazing years. 相似文献