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Showing papers on "Undergrowth published in 1998"


Journal ArticleDOI
TL;DR: In this article, the authors evaluated the potential environmental benefits of afforestation with pines (Pinus pinaster and, to a lesser extent, Pinea and P. halepensis) over large areas of dry cereal croplands in central Spain in the next 10-20 years.
Abstract: Summary Afforestation with pines (Pinus pinaster and, to a lesser extent, P. pinea and P. halepensis) seems to be the most probable land-use change over large areas of dry cereal croplands in central Spain in the next 10–20 years. This will be encouraged by changes in the subsidy policies of the Common Agricultural Policy that aim to decrease food production and restore the environmental diversity previously lost through agricultural intensification. This study addresses the factors influencing the richness and composition of breeding bird communities in these pine plantations and evaluates the potential environmental benefits of the afforestation programmes. The complement of bird species breeding in 88 plantations ranging in size from 0.1 to 6775 ha was determined. Plantations were characterized according to size, distance to the nearest large plantation, vegetation structure and geographical location (northern moist vs. southern xeric Iberian plateaux). Plantation size alone accounted for 67–75% of the variation in species richness, and was also the maintrait explaining the patterns of presence/absence of most individual bird species. Plantations smaller than 25 ha only maintained 50% of the regional pool of forest birds during breeding, whereas this proportion increased to 69–86% for plantations of 25–100 ha. Geographic location, degree of isolation and vegetation structure were also important. Bird species richness decreased with distance to a large plantation, and increased with prevalence of undergrowth shrubs and with plant species richness. Both species richness and the incidence of individual species in plantations were affected by geographical location. They were greater in plantations of the northern plateau, reflecting a trend of increasing densities of most forest bird species in Spain in more northerly locations. The results of this study suggest that re-afforestation of former arable land in the Spanish plateaux is unlikely to increase species richness in forest bird communities. Given the regional scarcity of many forest birds and the small scale of new plantations, re-afforestation schemes are unlikely to promote rich forest bird communities. Since plantations are unsuitable habitats for the bird species breeding in Spanish dry cereal croplands, and such birds have a high conservation value because of their small and declining populations the overall environmental benefits of large-scale afforestation programmes will not include increased diversity of birds.

150 citations


Journal ArticleDOI
TL;DR: The Netherlands is the country with the highest nitrogen deposition in Europe and approximately 2/3 of the nitrogen deposition is from NH x. Considering defoliation and discoloration of the foliage, tree vitality of Dutch forest is poor, and declining for some tree species.

80 citations


Journal ArticleDOI
TL;DR: Soil organic matter and litter quality are of main importance in changing the above- and below-ground habitat in plantations, and are correlated with soil pH and soil organic-matter content.

40 citations


Journal ArticleDOI
TL;DR: The distribution pattern in a 4-ha area of 11 selected primary forest canopy tree species revealed an overall trend in recolonisation of this species category in the secondary forest, which is largely dominated by secondary forest tree species forming a canopy that rarely exceeds 20 m.
Abstract: Secondary succession in a 19-y old tropical rainforest of French Guiana was investigated through the distribution pattern of primary forest species. The experimental plot of 25 ha was logged to simulate conditions of a paper pulp cut. Enumeration of all plants of height ≥ 50 cm in 52 subplots 10 m × 10 m indicated the number of species and individuals in five species categories; short-lived pioneer species, pioneer species that persist in mature forest, primary forest species capable of germinating in shade, primary forest species that indicate a preference for clearings (small gaps) in mature forest and understorey primary forest species. Change in proportion of the most abundant species (≥ 1 cm dbh) over the last 15 y indicated a decrease in short-lived pioneer species and an increase in pioneers that can persist in the mature forest. Proportion of species categories per height class indicated that primary forest species were mainly found in the lower height class in this forest which is largely dominated by secondary forest tree species forming a canopy that rarely exceeds 20 m. Individuals of primary forest species were encountered on ARBOCEL as sprouts from large stumps, sprouts from juveniles or as untraumatised saplings or juveniles. The distribution pattern in a 4-ha area of 11 selected primary forest canopy tree species revealed an overall trend in recolonisation of this species category in the secondary forest. Considered individually, the clustered distribution of stems of Eperua grandiflora showed the importance of regeneration through sprouting or remaining individuals. The gradient distribution, oriented from the edge to the centre of the studied plot, and displayed by the stem densities of Virola michelii, suggested a recent progressive dispersal of seeds. A more dynamic recolonisation front was observed for the primary forest understorey species Cassipourea guianensis and was probably linked to both the initial logging conditions and the fact that this species fruits when relatively young.

36 citations



Journal ArticleDOI
Joris De Wolf1
TL;DR: In this paper, a field survey consisting of 141 detailed releves of the tree and shrub crowns covered by species was performed, and a classification was obtained by isolation of groups of releves in the ordination diagrams obtained by detrended correspondence analysis (DCA). Associated releves were visually differentiated and removed from the data set to be used in subsequent DCA.

18 citations


Journal ArticleDOI
01 Jun 1998-Wetlands
TL;DR: The forest developed in conditions of low water levels, low salinity, and a hydroperiod that allows seed germination and seedling establishment during the early wet season, however, the forest undergrowth seems to be becoming dominated by terrestrial vegetation with palm seedlings unable to survive.
Abstract: Palm Swamp Forests in the Caribbean region have been little studied although they are found in many countries. In Trinidad, they are an important component of the vegetation in the Nariva Swamp, a Ramsar site. The distribution and ecology of plants inRoystonea oleracea Palm Swamp Forest was studied using selected study plots. The forest had an open canopy with palms up to 26 m tall and a density of trees ≥10 cm dbh of 380 per hectare. TheRoystonea palm contributed 55.8% of individuals and was the most important of seven tree species ≥10 cm dbh. Seventy-four species were found, with most being understory shrubs and herbs. Peak ripe fruit availability was from August to November and was correlated with rainfall. The palm forest canopy appears to be relatively even aged, with lower non-palm trees giving an all-aged height and dbh distribution in the forest. The forest developed in conditions of low water levels, low salinity, and a hydroperiod that allows seed germination and seedling establishment during the early wet season. However, the forest undergrowth seems to be becoming dominated by terrestrial vegetation with palm seedlings unable to survive.

18 citations


Journal Article
TL;DR: This study sets out to provide systematic data on bird assemblages in Irish plantation forests, and to suggest ways in which the biodiversity, as represented by birdlife, might be enhanced.
Abstract: Forest expansion in Ireland has led to concern for the characteristic plant and animal communities associated with the planted land. If carefully planned, however, forestry may provide opportunities for conservation and enhancement of biodiversity. This study sets out to provide systematic data on bird assemblages in Irish plantation forests, and to suggest ways in which the biodiversity, as represented by birdlife, might be enhanced. Preliminary data are presented on the general bird assemblages of 'mature' (pole-stage) forests in southwest Ireland during spring/summer, autumn and winter 1996/97, and on bird/habitat relationships. A total of38 bird species was recorded within the 20 forest compartments studied, with goldcrest (Regulus regulus) being the most abundant and widespread. Some species showed marked seasonal variation in forest usage. Habitat factors which showed a positive relationship to bird species richness and/or bird density included, on varying scales, the number of broadleaf species present, proximity to the forest edge, and the amount of undergrowth. Some bird species also showed evidence of association with particular species of conifer.

14 citations



Journal ArticleDOI
TL;DR: The process of extinction of the Salix population - observed over 19 yr on permanent plots with marked trees - proceeded very quickly, especially in the first decade of observation, and led to the almost complete disappearance of S. caprea from the forest communities of Bialowie2a National Park.
Abstract: Broadleaved forest communities degenerated through strong pressure from large herbivores. Relief of this pressure led to regeneration, in particular of Salix caprea and other light-seeded pioneer trees: Populus tremula, Betula pendula and B. pubescens. This regeneration proceeded fol- lowing conservation protection of degenerate stands in a na- ture reserve and later in Bialowie2a National Park. The emer- gence and development of the Salix caprea population pro- ceeded following the expansion of Picea abies, which coin- cided with the period of enhanced animal pressure on the broadleaved forest. Salix caprea filled all the gaps in the tree stand after the destruction of trees and undergrowth by herbiv- ores (in the years 1892- 1915). The species also appeared abundantly in old, at the time unforested, clearings and felled areas. Here, S. caprea developed large populations with certain trees in good condition, with a growth form typical of forest trees and attaining considerable heights. The majority of trees were 50 - 60 yr old at the time of death, although some individuals reached 74 yr of age. The process of extinction of the Salix population - observed over 19 yr on permanent plots with marked trees - proceeded very quickly, especially in the first decade of observation. It led to the almost complete disappearance of S. caprea from the forest communities of Bialowie2a National Park. The death of individual trees is

8 citations


Journal ArticleDOI
TL;DR: The results of the Symposium on "Deforestation and reforestation: The Atlas Project" as mentioned in this paper showed that at present the causes of deforestation do not arise so much from global climatic causes, but rather from human activity.
Abstract: This paper presents the results of the Symposium on “Deforestation and reforestation: The Atlas Project”. From the studies presented appeared that at present the causes od deforestation do not arise so much from global climatic causes, but rather from human activity. Both the study conducted on the Nokopo population in Papua New Guinea, by Kocher Schmid, and the one conducted on the Berbers in Morocco, by Camperio Ciani and Arhou, presented a clear role of the local population and its tradition on negatiove forerst iopact. Agro-forestal grazing and clearing for domestic animal feeding produced heavy forest degeneration. In Morocco the role of mixed herds of a few goats with many sheep produce devastating effects to the undergrowth of the Cedar and Oak forest. While fires ang pig overgrazing produce deforestation in the Nokopo Primary forest region. Further the external impact of foreign culture negatively affects the dinamic relationship between the local culture and the forest environment. The desertific...


Journal Article
TL;DR: The suppressive effect of Nuclea latifolia and Pterocarpus santalinoides the understorey growth might have been due to allelopathic effects caused by secondary metabolites leached from the tree canopy during precipitation or from the floor litter during decomposition.
Abstract: Planted fallows of seven multipurpose tree species were analysed in order to reveal their impact on understorey vegetation in South-Western Nigeria. Although having light environment under their canopy comparable with most of the other tree species, Nuclea latifolia and Pterocarpus santalinoides had the lowest density and biomass of understorey vegetation. Only Milletia thoningi had lower understorey biomass than these two tree species although it had higher understorey density. Soil fertility was not a limiting factor for the undergrowth since those three species which had the highest undergrowth density and biomass had either comparable or lower fertility status. This implies that, the suppressive effect of Nuclea latifolia and Pterocarpus santalinoides the understorey growth might have been due to allelopathic effects caused by secondary metabolites leached from the tree canopy during precipitation or from the floor litter during decomposition. Because of the limitations imposed by the lack of randomisation of the tree stands in the site, conventional analysis of variance was not appropriate. Instead, the calculated means for each variable was used to compare the results.