Management Effects on Biomass and Foliar Nutritive Value of <Emphasis Type="Italic">Robinia pseudoacacia</Emphasis> and <Emphasis Type="Italic">Gleditsia triacanthos</Emphasis> f. <Emphasis Type="Italic">inermis</Emphasis> in Arkansas,USA

The browse potential of black locust (Robinia pseudoacacia L.) and thornless honey locust [Gleditsia triacanthos f. inermis (L.) Zabel] has not been adequately tested. Our objective was to determine effects of fertilization and pollarding on biomass and foliar nutritive value in separate studies of black locust and thornless honey locust in Arkansas, USA. Shoots were sampled monthly for two consecutive growing seasons in 2002 and 2003 to determine foliar, shoot, and total aboveground biomass, shoot basal diameter, and foliar nutritive value (crude protein and in vitro digestibility). Black locust yielded more foliar biomass when pollarded at 50 or 100 cm and fertilized with 600 kg P ha⁻¹, than at 5 cm with or without P, averaging 3.5 Mg dry matter ha⁻¹. Black locust foliar crude protein and in vitro dry matter digestibility ( ≤ 170 and 534 g kg⁻¹, respectively) decreased as leaves aged, but still met maintenance needs for beef cattle (Bos taurus L.). Thornless honey locust had little agronomic potential because of slow establishment, low foliar yield (330 kg ha⁻¹), and a 2% reversion to undesirable thorny phenotype. Black locust should be considered for livestock browse when drought induces semi-dormancy of herbaceous forages.     

Modified Pollard transects for assessing tropical butterfly abundance and diversity

This paper introduces and discusses the consistency and effectiveness of an inexpensive modification of Pollard transects for assessing the diversity and abundance of tropical butterfly communities in two national parks in Rio de Janeiro, Brazil. To measure butterfly abundance, students walked simultaneous timed transects at the interface of forest and cleared areas. They either counted the number of individuals observed or tabulated the number of specimens collected with nets. After a short training period, the number of butterflies observed or collected on simultaneous transects was statistically indistinguishable among student groups, and there was a significant positive correlation between observation counts and collected number of individuals. As a measure of species richness, the number of butterfly species sampled on each simultaneous transect was tabulated and did not differ statistically. To measure diversity, alpha of the logseries model was calculated for each collected sample, and statistical fit to a logseries model was determined. Although virtually all daily samples and the year's accumulated sample at one park fit the logseries model, about 35% of the daily samples and the entire year's sample did not fit at the other park. Despite these differences between the two parks, values for alpha from daily samples at both parks varied similarly (from 15 to 50 in almost all cases), and values from the entire year's samples were statistically indistinguishable. The repeatability of results among novices, such as students, suggests that timed transects have great promise for furthering our understanding of butterfly community demographics.     

杨树长截干深栽分阶段作业法造林效果分析

杨树截干苗造林是北方干旱地区主要造林方法之一，采用“长截干分阶段作业”可真正做到“三埋两踩一提苗”该法将苗木截干部位从距地表１８ｃｍ提高到３５～３８ｃｍ挖径，深各６０～７０ｃｍ植苗坑，两次填土踩实分阶段作业，分别验收，该法一般造林成活率达到９８％，以上，２～３年树高和胸径分别增加４．２３％和１０．５７％。     

江苏蝴蝶动态监测数据库建立的初步设计

从江苏蝴蝶生态监测的现状和需求出发,以江苏境内蝴蝶的部分种为例提出建立江苏蝴蝶动态监测数据库的设计方案。     

Role of income diversification in protecting natural forests: evidence from rural households in forest margins of Sri Lanka

Ranchers need alternative livestock feeds when herbaceous forages become limiting in summer. Our objectives were to determine: (1) leaf and stem biomass components, (2) nutritive value [in vitro dry matter digestibility (IVDMD), total nonstructural carbohydrate (TNC), N, and N digestibility] of leaves for animal browse, (3) concentration of the secondary metabolites robinin and mimosine, and (4) in vitro leaf and bark toxicity for black locust (Robinia pseudoacacia L.) and mimosa (Albizia julibrissin Durz.), respectively, pollarded at 50 cm in Arkansas, USA. Black locust exceeded mimosa for every yield component (leaf mass tree⁻¹, leaves shoot⁻¹, shoots tree⁻¹, shoot mass tree⁻¹, stem basal area, and biomass tree⁻¹) except mass leaf⁻¹. Projected yields were 1,900 and 1,600 kg leaves ha⁻¹ for black locust and mimosa, respectively, assuming a population of 12,300 trees ha⁻¹. Mimosa leaves had greater IVDMD, TNC, and N digestibility than black locust. Mimosa leaves exceeded the nutritional N requirements of growing cattle (Bos taurus L.) and goats (Capra hircus L.), but protein supplementation would be needed for growing goats grazing black locust leaves. Tissue concentrations of secondary metabolites robinin and mimosine were below detectable limits in black locust and mimosa, respectively. The extract of black locust bark, but not leaves, was toxic to bioassayed African green monkey (Cercopithecus aethiops L.) cells. Either black locust or mimosa could provide moderate quantities of high quality, rotationally grazed forage for goats during summer months when herbaceous forage may in short supply.