检索结果-南通市图书馆

Stand dynamics of the drought-affected floodplain forests of Araguaia River,Brazilian Amazon

在线全文

学校读者我要写书评

暂无评论

Forest Ecosystems 2017年第3期4卷 201-210页

作者： Jürgen Homeier Dariusz Kurzatkowski Christoph Leuschner Plant Ecology Albrecht von Haller Institute for Plant Sciences University of Goettingen

Background： The floodplain forests of Araguaia River, a clear-water river in the southeastern Amazon（Tocantins State, Brazil）, are characterized by seasonal flooding up to 3.5 m height, low nutrient levels in the water, and seasonal drought periods of 4–5 ***： We studied the forest dynamics（tree diameter growth, tree mortality and recruitment） of this unique forest ecosystem over a 5-year period by repeated censuses in 12 permanent plots established along a flooding ***： The cumulative basal area in the plots increased by 0.84（±0.45） m^2·ha^-1·yr^-1（mean ±SD） in the annual y-flooded（AF） plots in lower terrain and by 0.69（±1.00） m^2·ha^-1·yr^-1 in the higher non-annual y flooded（NAF） plots, corresponding to an aboveground biomass increase of 0.81（±0.57） and 0.69（±1.58） Mg·ha^-1·yr^-1 in the AF and NAF plots, indicating a recent carbon sink in the biomass. Mean diameter growth rate was 1.8（±0.44） mm·yr^-1 in the AF and 2.0（±0.56） mm·yr^-1 in the NAF plots（corresponding to a coarse wood production of 1.53（±1.29） and 2.02（±0.52） Mg·ha^-1·yr^-1）,indicating no flooding effect on radial growth. Mean mortality rates in the 5-year period were 1.9（±0.37）·yr^-1 in the AF plots and 1.8（±0.87）%·yr^-1 in the NAF plots with no differences along the flooding gradient. Highest mortalities were registered in the AF plots for the 10–20 cm dbh class（2.4%·yr^-1）, likely as a consequence of flooding,and in the NAF plots for the 40–50 cm dbh class（3.0%·yr^-1）, probably mainly caused by ENSO-related ***： We conclude that these drought-affected tropical floodplain forests have a lower standing biomass and aboveground productivity than central Amazonian floodplain forests in more humid climates, and the imprint of the flooding gradient on stand dynamics is relatively weak, which may result from the lower flooding height and the interaction of flooding with low nutrient supply and periodic drought.

关键词： Amazon diameter growth Dry season Flooding regime Mortality rate Productivity Tree recruitment

Effects of different land-use systems (grazing and understory cultivation) on growth and yield of semi-arid oak coppices

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2020年第6期31卷 2235-2244页

作者： Ali Soltani Hamdollah Sadeghi Kaji Saleh Kahyani Department of Forest Science Faculty of Natural Resources and Earth SciencesShahrekord UniversityP.O.Box 115ShahrekordIran

The present study examines the extent of negative eff ects of traditional multiple land-use systems on oak coppices,from a forest management point of *** study area was located in approximately 10,000 ha of hilly Brant’s oak(Quercus brantii Lindl.)woodlands in the central Zagros *** the same site-quality class,three land-use systems were compared:simple coppice(Co),coppice in conjunction with small ruminant grazing(CoG),and coppice with understory rain-fed wheat cultivation plus grazing(CoCG).Data on total wood volume of trunk and major branches,and annual ring growth,were collected and analyzed from 74 stands in 15 coppiced woodland *** results showed the advantage of Co over CoG and CoCG land-uses by 43 and 60 m 3 of mean accumulated wood volume per hectare,*** diameter growth analysis also revealed an annual increase in wood production of trees in Co land-uses over 43 years,with an exception of the recent decade,when growth coincided with a severe *** a back-extrapolation method,the minimum rotation age of woodlands in Co land-use was found to be 23.6 years,5 and 7 years shorter than those of CoG and CoCG land-uses,*** CoCG,woodlands located in Co and CoG land-use systems demonstrated a high level of agreement with self-thinning rule of−3/*** for the stand density index for coppiced oak woodlands were between more than 1000 for the least disturbed(Co)and less than 400 for the most disturbed woodlands(CoCG).The structure and growth rate of the coppiced oak woodlands were irreversibly disrupted by understory tillage plus grazing and in less extent by grazing *** was concluded that ending undergrowth cultivation in semi-arid oak coppices should be addressed as a priority by adopting minimum regulations.

关键词： Coppicing Land-use impact assessment diameter growth Multi-purpose land-use Self-thinning rule Stand density index

Effect of first thinning and pruning on the individual growth of Pinus patula tree species

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2015年第4期26卷 827-831页

作者： Edward Missanjo Gift Kamanga-Thole Malawi College of Forestry and Wildlife

The effect of first thinning and pruning on height, diameter at breast height （DBH）, and volume growth was studied in individual trees of Pinus patula Schiede and Deppe in Chongoni Plantation, using four plots for thinning trials. Each of the plots was 0.5 ha and subjected to one of the fol- lowing silvicultural treatments： first thinning and pruning, first thinning and no pruning, pruning and no thinning, and control （no pruning and no thinning）. The silvicultural treatments were randomized in four replicates. Fourteen years after planting, the following parameters were measured including total height, DBH, and volume. The highest DBH and volume growth was observed in thinning and pruning, while the highest growth in height was observed where there was pruning and no thinning. Clearly, both thinning and pruning are an important manage- ment option in pine species plantations in Malawi to maximize the increase in volume productivity.

关键词： Pinus patula Thinning and pruning diameter growth Height growth Volume

Modelling growing space of four valuable broadleaved tree species in southern China

在线全文

学校读者我要写书评

暂无评论

Forestry Studies in China 2013年第3期15卷 167-178页

作者： Johanna SCHULER Josephine CUENI Heinrich SPIECKER Wen-Fu GUO Faculty of Environment and Natural Resources Albert-Ludwigs-Universitt Sci-Tech Division of the Experimental Centre for Tropical Forestry Chinese Academy of Forestry

We present management tools for growing four valuable broadleaved tree species, indigenous to *** southern China. Crown diameter （CD） of the species studied can be predicted very well by using a model that is so e y a near funct on of d ameter at breast he ght （DBH）. The add t on of tree age （AGE） and yield class （YC） to this-nodel did not significantly improve its predictive capacity. We used species-specific crown diameter models to calcu- ate the amount of growing space and subsequently stand density that each species needs to achieve desired stem ＂adial growth rates. Furthermore we used this information to calculate a ＂distance factor＂, a rule of thumb that roughly ~stimates the distance between two neighboring trees needed to achieve a desired future target diameter. These tools ＇acilitate the planning of thinning regimes by using crown diameter models combined with annual radial growth rates to ;alculate the number of crop trees per hectare required to reach a desired target stem diameter.

关键词： crown diameter diameter growth growth model valuable timber management tool

Investigating the Impact of Climate Changes on Qualitative and Quantitative growth of Oak Trees (Case Study: Central Zagros)

在线全文

学校读者我要写书评

暂无评论

Open Journal of Ecology 2016年第6期6卷 358-366页

作者： Morteza Habibi Department of Forestry Faculty of Science and Research University of Islamic Azad Tehran Iran

The present study is an attempt to investigate the impact of climate changes on quantitative and qualitative growth of oak trees in central Zagros region. After we selected the study region, 35 discs were taken from trees felled in each height class (e.g. 1400 - 1600, 1600 - 1800, 1800 - 2000 m above the sea level). We used climate index spi. For the data analysis, we employed SPSS software and inferential statistics tests of Kolmogroff Smirnov and the one-way ANOVA. During the recent 15 years, rainfall has shown a decreasing trend and amount of haze and frequency of occurring haze has been increased. The ANOVA results indicated that diameter growth of trees in three height classes revealed a significant difference. The average annual diameter growth in the first, second and third classes were 1.8 mm, 2.5 mm, and 2.2 mm, respectively. Additionally, the results indicated that hillsides and slope aspect has a statistically meaningful effect on the size of canopy area, basal area and number per hectare. Several different studies have reported that during the recent 15 years, qualitative and quantitative growth of central Zagros oak trees strongly correlate with climate parameters in the three habitats.

关键词： Iranian Oak Coppicing Central Zagros diameter growth Slope Elevation Temperature Rainfall Haze

Effects of Lithological Characters on the growth of Cunninghamia lanceolata

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Agricultural Science & Technology 2009年第6期10卷 94-96,107页

作者：刘映良谢双喜丁贵杰贵州师范大学生命科学学院贵州贵阳550001 贵州大学造林生态研究所贵州贵阳550025

Objective The aim was to reveal relationship between lithological character soil and productivity of Cunninghamia lanceolata and lay a foundation for systemic management of C. lanceolata fast-growing and high yield plantation. Method By using experimental ecology method and variance analysis, the biomass and growth of planting eleven years＇ C. lanceolata on the soils with six different lithologicel characters were studied. Result The effects of soils with six different lithological characters on the height, diameter growth and biomass of C. lanceolata were different, in which the growth order of C. lanceolata was： Feldspathic quartzy sandstone （ average height 523. 270 cm, average diameter 4.720 cm, average individual biomass 5.059kg）〉 Basalt （ average height 511. 570 cm, average diameter 4.650 cm, average individual biomass 4.848 kg）〉 Quartzy sandstone 〉 Blastopsammite 〉 The Quarternary Period red clay 〉 Coal-series siliceous sand-shale, and the difference was smaller between the last two lithological characters. Conclusion Feldspathic quartzy sandstone and Basalt are beneficial to C. lanceolata.

关键词： Cunninghamia lanceolata Lithological character Height growth diameter growth Biomass