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Spatial pattern of trees of different diameter classes in managed pine stands (Pinus sylvestris L.) of different age

100%

Szmyt J.

Acta Scientiarum Polonorum. Silvarum Colendarum Ratio et Industria Lignaria

2010

tom 09

nr 3-4

The present research was conducted in managed stands of Scots pine (Pinus sylvestris L.) at different age in Poland. All the investigated stands were planted and thinned according to selection thinning. Analysis of spatial structure concerned trees of different categories (DBH classess) depending on the age of stand. Spatial distribution of trees was investigated using two commonly used methods: Clark-Evans R index and Ripley's L(t) function. In stands of age 43 and 65 the effect of the initial spacing was observed and all living trees were distributed regularly at the smallest distances and at larger spatial scale they were spaced randomly. Random type of spatial structure of trees was observed when smaller and larger trees were taken into consideration, separately. In case of stands at the age 90 the effect of the initial planting on the spatial structure of trees was not observed even at the smallest distances independently of the category of trees taken into account. All living trees in these stands were distributed randomly. Only in two stands clumps of trees were observed and one concerned smaller trees and the other - larger trees. Size differentiation index was small for all stands. The lowest values was ascertained in the oldest stands.

Structural diversity closely associated with canopy species diversity and stand age in species-poor montane forests on Loess Plateau of China

100%

Liu N., Wang H., Nan H.

Polish Journal of Ecology

2017

tom 65

nr 2

High species diversity is often accompanied with and supported by a diversified stand structure in species-rich natural forests. However, the relationship between species diversity and stand structural diversity is less examined in species-poor forests. In montane forests on Loess Plateau of north-central China in a semi-arid climate zone, canopy species diversity and vertical structure of 57 broadleaves, conifer and mixed stands, with varying stand ages and site conditions, were randomly sampled. Canopy species diversity was represented by Shannon's index (H'). Stand structural diversity was represented by two indices respectively, i.e. coefficients of variation of diameter measurements at breast height (CVdbh) and Shannon's index of diameter classes (H'dbh). Structural equation models (SEMs) were constructed to explore multiple relationships between stand structural diversity and canopy species diversity, stand age and elevation. Both stand structural diversity indices increased directly with H' and stand age. However, indirect positive effect of stand age via increasing H' was only significant on CV. H'dbh provided positive feedback on H', while effect of stand age was only indirect via increasing structural diversity. Elevation significantly affected coefficients of variation of diameter, which was probably a sampling effect due to narrow distribution of broadleaves-conifer stands in altitudinal range. In conclusion, the results showed that stand structural diversity and canopy species diversity and stand age are closely associated with the species-poor montane forests like these on Loess Plateau of north-central China.

Ograniczanie wyników

1 Acta Scientiarum Polonorum. Silvarum Colendarum Ratio et Industria Lignaria

1 Polish Journal of Ecology

1 Liu N.

1 Nan H.

1 Szmyt J.

1 Wang H.

1 2017

1 2010

Wyniki wyszukiwania

Spatial pattern of trees of different diameter classes in managed pine stands (Pinus sylvestris L.) of different age

Structural diversity closely associated with canopy species diversity and stand age in species-poor montane forests on Loess Plateau of China