Showing papers on "Undergrowth published in 1997"

Disturbance, selective logging and bird diversity: a neotropical forest study

Abstract: The composition and structure of bird communities, and the damage to forest structure were surveyed in northern French Guiana (northeastern Amazonia) one year and ten years after selective logging and compared with the situation in a similar undisturbed primary forest. A point-count method was used in which 937 0.25ha sample plots were censused for 20 minutes each, and their vegetation structure was measured. On average, 38% of the forest undergrowth was destroyed, then invaded by dense regrowth, and up to 63% of the canopy was substantially opened as a result of selective logging. Hunting pressure also increased due to access roads opened for logging. Among the 256 species recorded, overall bird species richness and abundance were depressed by 27–34% in the logged areas compared to primary forest. The most vulnerable guilds, which decreased by 37–98% in abundance, were mature forest understorey species, especially terrestrial ones and mixed flocks of insectivores. Hummingbirds, small gaps, vine tangles and canopy species did not decrease, nor increase significantly after logging. Only species naturally associated with dense second growth, forest edges and large gaps actually increased. Habitat specialization was the major determinant of vulnerability to logging, and, to a lesser degree, size (large) and diet (insectivorous), but foraging behaviour and rarity had little effect. Bird sensitivity to changes in logged forest structure may involve physiological intolerance, reduced food categories, increased exposure to predators, too dense understorey for their specific foraging behaviour and/or avoidance of gaps. Suggested improvements of current forest management and logging techniques for the maintenance of a higher proportion of the original biodiversity include minimizing logging damages, long rotations (>50 years) between cuts, and keeping unlogged forest patches within logging concessions.

Effects of undergrowth removal on the species diversity of insects in natural forests of Okinawa Hontô

Abstract: Yanbaru, the northern montane part of Okinawa Honto (the main Island of Okinawa), is an important area for nature conservation, with many endemic and endangered species, such as Pryer's Woodpecker Sapheophipo noguchii and Okinawa Rail Rallus okinawae. The climax community of Yanbaru is a subtropical, evergreen, broad-leaved forest dominated by oaks, with a dense undergrowth of broad-leaved small trees, herbs and ferns.

A protocol for measuring abundance and size of a neotropical liana, Desmoncus polyacanthos (Palmae), in relation to forest structure

Abstract: This study investigated the relationship between the abundance and size ofD. polyacanthos and measures of forest canopy structure. Varzea and terra firme forest were selected for study at the mouth of the Amazon estuary, Para, Brazil. The forest canopy characteristics investigated included individual tree height and height to base of the live portion of the crown, forest canopy depth (the distance from the lowest foliage in the understory to the top of the canopy including all free space between top and bottom), forest canopy thickness (the portion of the forest canopy depth occupied only by foliage) and forest canopy density (the sum of lengths of each of the individual crowns that make up forest canopy depth) (see Fig. 2b). The attributes ofD. polyacanthos measured included leaf number, stem height and percent coverage within the stands. Results from this study suggest thatD. polyacanthos can be encouraged to grow through selective cutting of canopy trees and promotion of regenerating forest stands on terra firme fallow. The protocol used to relateD. polyacanthos abundance and size to kind of forest canopy structure can be used for evaluation of other climbing palms.

Effects on forest ecosystems

Abstract: Publisher Summary This chapter discusses the results of research on the effects on forests, which was central in the Dutch Priority Programme on Acidification (DPPA) The chapter deals with the results of laboratory experiments and of the monitoring and manipulating of forest stands—including the modelling of these field results, with regional inventories of forest vitality and soil chemistry and with research on non-tree biotic components of forest Seedlings of Douglas fir were used in a pot experiment to study the effect of fertilizing with 100 kg N ha -l y -1 on the biomass production and in particular on the specific root length (length/weight) The results of these experiments indicate that applying nitrogen can lead to an increase in the shoot/root ratio and can also cause damage to the root system It also appears that the response depends not only on the amount of nitrogen supplied to the plant but also on the form in which it is offered The chapter focuses particularly on tree physiology and research on the chemistry of soil and water, together with the tree vitality Various aspects of forest undergrowth and forest fauna are dealt and the results are evaluated in the light of critical levels and loads

Plant diversity of Pinus koraiensis forests under disturbance in the Changbai Mountains of China.

Abstract: The results show that the diversity of the whole community and undergrowth of B. platyphylla secondary forest are higher than that of any type of P. koraiensis forests. The diversity of the whole community and tree layer of P. koraiensis virgin forest with slight-selecive cutting are the highest among all P. koraiensis forests, which is the result of the forest adapting long term succession and species adaptation. Because B. platyphylla forest is in the second succession stage, more shade-tolerant tree species had colonized the community. Besides, solar radiation is the B. platyphylla forest is better, so that the undergrowth developed well, and the diversity of woody plant is very high. At last, the relationships between diversity and evenness, haibtat of the communities are analysed.

Plant diversity of pinus koraiensis forests under disturbance in changbai mountains of china

Abstract: A comparison was made on the plant divenity of Pinus koraiensis forest after selective cutting and Betula platyplla secondary forest formed after clear cutting in the Pkoraiensis forests in Changbai Mountain forest region in China The results show that the divenity of the whole community and undergrowth of B platyphyllasecondary forest are higher than that of any type of P koraiensis forests The divenity of the whole community and tree layer of P korairensis virgin forest with slight- selective cutting are the highest among all P koraiensis forests, which is the result of the forest adapting long term succession and species adaptation Because B platyphylla forest is in the second succession stage, more shade- tolerant tne species had colonized the community Besides, solar radiation is the B platyphylla forest is better so that the undergrowth developed well, and the diversity of woody plant is very high At last the relationships between diversity and evenness, haibtat of the communities are analysed

Ecological Impact of Compaction under Teak Plantation in the Foothill of Darjeeling Himalaya

Abstract: Ecological study under Teak plantation of 1968 in the foothill of Darjeeling Himalayas reveals that due to compaction of forest floor, decrease in height, diameter and basal area of Teak trees were in order of 8.3, 16.4 and 34.7 percent respectively. It may be due to less porosity and much bulk density of the soil. Due to compaction of the forest floor, species density of the undergrowth was 121.93% more than controlled area. Whereas species diversity was 68.30% less than controlled forest floor. Compactin leads presence of Paspalum sanguinalle and Oplismenus burmannii grasses having their value of 69.47 and 21.56 density/m 2 whereas their presence in controlled forest floor were 21.14 and 4.80 respectively. So, result indicates that grasses are compaction resistants under controlled forest floor. Correa bengalensis a shrub represents 75% of its distribution. From compacted forest floor undergrowth biomass production was 1.150 ton/ha and from controlled floor, it was 2.584 ton/ha. So decrease of undergrowth production from compacted forest floor was 124.69 percent. Result also indicates that in compacted forest floor, fodder quantity was 1152.94 percent more than miscellaneous undergrowth biomass production. So, the result indicates that due to compaction of Teak plantation, productivity of Teak trees and its undergrowth decreases. This may be due to less porosity and much bullk density of the soils which has direct link with intake of water. Any biological activities under forest floor should be avoided for conservation of soils and water for better productivity point of view.

Method for controlling weeds and undergrowth using hot water spray and foam

Abstract: A method for controlling weeds and undergrowth and for treating plants in agricultural settings is disclosed. The method is characterized by first applying spray of hot water to the plant, and then applying a foam blanket to the sprayed plants, whereby heat from the hot water spray is held against the plants.