Witold Pazdrowski

Modelling needle biomass in Scots pine (Pinus sylvestris L.) stands on former farmland and forest soils

Model biomasy igliwia sosny zwyczajnej (Pinus sylvestris L.) wyrosłej w warunkach gruntów porolnych i leśnych Modelling needle biomass in Scots pine (Pinus sylvestris L.) stands on former farmland and forest soils The relationship between the biometric traits of Scots pine (Pinus sylvestris L.) trees and their total needle biomass was analysed and the foliage of these trees growing in 38 stands in northern and western Poland was modelled. Productive pine stands were chosen on former farmland and forest soil providing locally optimal conditions for growth. A total of 114 trees aged between 32 and 114 years old were felled and their total biomass of fresh needles was calculated. Out of all the traits measured, diameter at breast height (DBH) was the best predictor of foliage biomass. Since the two models produced to describe this relationship on forest soils (Mi = 0.093614 D1.31.679398), and farmland (Mi = 0.060302 D1.31.819009) were very similar, they may be used interchangeably. However, as they aged, needles of pines growing on former farmland deteriorated faster than those on forest soil with respect to their assimilation capacity. This suggests that the assumptions of Pipe Model Theory need to be verified.

Selected properties of wood in Scots pine (Pinus sylvestris L.) growing on post-agricultural land in northern Poland

Właściwości drewna sosny zwyczajnej (Pinus sylvestris L.) na gruntach porolnych w północnej Polsce Selected properties of wood in Scots pine (Pinus sylvestris L.) growing on post-agricultural land in northern Poland Analyses were conducted on wood of Scots pines collected from timber stands growing on post-agricultural land and forest land in the fresh coniferous (Bśw) and fresh mixed coniferous (BMśw) forest habitats located in the territory of the Miastko Forest District. The wood of pines growing on post-agricultural land in the BMśw habitat conditions had the highest basic density and lowest compression strength along the grain among the tested sample groups. The arrangement of wood properties was not typical with regard to the social position of trees in a stand. The obtained results have shown the lack of a direct relationship between wood basic density and compression strength along the grain. The analyses performed pointed to differences in the properties of wood tissues between pines growing on post-agricultural land and pines growing on typical forest soils.

Self-pruning of pedunculate oak (Quercus robur L.) stems and the diameter at breast height of trees in commercially managed stands

Proces oczyszczania się pni dębu szypułkowego (Quercus robur L.) a pierśnica drzew w drzewostanach gospodarczych Self-pruning of pedunculate oak (Quercus robur L.) stems and the diameter at breast height of trees in commercially managed stands The focus of this study was on the knottiness and self-pruning of trees at 10 study sites from which 30 trees were selected for observation. These areas represent two main forest site types (fresh mixed deciduous forest - LMśw and fresh deciduous forest - Lśw) characteristic of the silvicultural regime of oaks in Polands lowland area. Sample trees were selected according to the principles of the Urich method (with the same number of trees in the diameter class) and Krafts biosocial classification. Trees from the dominant stand (class I, II and III according to Krafts classification) were subjected to analysis. Normal distribution of length parameters was found for the majority of analysed zones of sample trees. On this basis correlation values were calculated describing the relationships between the diameter at breast height (dbh) and self-pruned zones on the stem: with knobs visible on external surface of tree stem, with snags remained after the dead branches, with the still unbroken dead and dying branches, live crown (active with regard to transpiration and photosynthesis). The length of the self-pruned tree stems from the fresh deciduous forest was greater in comparison with the trees from the fresh mixed deciduous forest. In turn, the length of the knob and snag zones was greater in trees from the fresh mixed deciduous forest. The variation in these parameters was rather insignificant. No statistically significant differences were detected in mean lengths of the examined zones between the two forest site types. Trees in the oldest age classes (VI and VII) showed a higher mean length of individual stem zones compared with those in younger age classes.

Correlation between selected elements of wood macrostructure and maturity of Scots pine (Pinus sylvestris L.) growing on post-agricultural land

Wybrane elementy budowy makrostrukturalnej drewna a dojrzałść sosny zwyczajnej (Pinus sylvestris L.) wyrosłej w warunkach gruntów porolnych Correlation between selected elements of wood macrostructure and maturity of Scots pine (Pinus sylvestris L.) growing on post-agricultural land The study was an attempt of comparing quantitative changes over time in selected wood macrostructural elements of Scots pines growing on former farmland, with those in trees growing on typical forest soils. The analysis was conducted on the basis of easily-determinable quality indexes taking into consideration average width of annual rings and the proportion of latewood in 5-year increment periods, the proportion of juvenile wood (Vm) and the proportion of heartwood (Vt). The study also compared selected biometric characteristics of trees, i.e. height (h), diameter at breast height (d), length (lk) and width (dk) of live crown; total stem volume (Vc) and determined a total of 48 model trees from 16 sample stands in age classes II, III, IV, V and higher. The radial dynamics of changes in annual ring widths was higher in trees from former farmland. In contrast, the proportion of latewood was similar in trees in all age classes and in trees growing on both soil types. In three out of four age classes analyzed in this study, the proportion of juvenile wood was higher in trees growing on typical forest soils, while the proportion of heartwood was higher in trees from former farmland. Taking into consideration the above observations it may be assumed that the Scots pine trees growing on former farmland reached technical maturity faster. However, this conclusion needs to be verified on a larger sample of model trees.