Productivity of grey alder (Alnus incana (L.) Moench) stands
2007
Miezite, O., Latvia Univ. of Agriculture, Jelgava (Latvia) | Dreimanis, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
Area of grey alder stands is 190.6 thousand ha that is 6.8% of the total area of forests in Latvia with average volume 31.3 million m**3 4.9% of total yield is in the state forests, but 95.1% in the forests of other managers. Scientific literature affirms that grey alder is easy growing trees species. Its stands are quick - growing and wood has high heating capacity. Empirical data in 1 - 10 years old stands are collected from 25 m2 sample plots, 15 in each stand. Data from older (11 - 30 years) stands are obtained by 6 - trees - sample - plot method, from 180 trees in each stand. Number of trees (y) in the stands diminishes with age (x) that is characterized by regression equation y = 72534xE-1.1488. The division of the number of trees in diameter classes characterizes distribution of trees diameters in stands and trees differentiation processes within the stands. At the age of 1 - 5 years, grey alder stems were in diameter classes under 2 cm but at the age 6 - 10 years - 2 and 4 cm. In 11 - 15 years old stands 89% of all the measured trees are included in four (4 - 10 cm) diameter classes. It pointed to growing differentiation of diameters of the trees. Starting from age 16 - 20 years, 76 - 89% of the trees were of four to five diameter classes (10 - 18 cm). The average standing volume in 11 and 15 year old stands was 110 m3 haE-1 and it increased step by step to 180 m3 haE-1 in the stands of age 26 - 30 years. The basal area in the age of 15 - 30 years varied between 20 - 26 m2 haE-1. The average diameter reached 15 cm in stands of 25 -30 years.
اظهر المزيد [+] اقل [-]