Growth and Yield of 15-Year Plantations of Pine, Spruce and Birch in Agricultural Land

The growth data and the potential returns from 15-year-old plantations of pine Pinus sylvestris L. (6 trial sites), spruce Picea abies Karst L. (9 trial sites) and silver birch Betula pendula Roth (13 trial sites), established in abandoned agricultural lands in a variety of soil types (sod calcareous, anthrosols, podzolic, podzols, gley, podzolic gley, alluvial), using the planting density 2,500 and 3,300 and also 5,000 trees/ha are analysed.

For tree plantations in agricultural soils (alluvial sod-gley, gley-sod podzolic, sod-podzolic gley, typic podzol) at the survival of 80-98% the stock volume for 15-year pine is as high as 102-155 m³ha⁻¹ with the volume growth 5.72-8.94 m³ha⁻¹ per year; the same indices for spruce in agricultural soils (gley sod-calcareous, sodpodzolic, cultivated, sod-podzolic gley, alluvial sod-gley, base-unsaturated brown) are 75-98 m³ha⁻¹ and 10.26-15.76 m³ha⁻¹, respectively. For 15-year plantation birch the mentioned indices may vary from 61 to 169 m³ha⁻¹ and from 7.54 to 29.82 m³ha⁻¹ per year. The lowest volume growth (4.66 m³ha⁻¹ per year) is for birch in heavy clay soil (gleyic sod-podzolic), the highest (29.72-29.82 m³ha⁻¹ per year) – in cultivated soils and pseudogley soil.

Plantation cultivation of pine, spruce and birch in agricultural lands may by the age of 15 years yield with a profit such forest products as pulpwood, fire wood and woody biomass. The gross income gained from first commercial thinnings of plantation pine, utilizing pulpwood, fire wood and logging residue biomass, may vary from 679-2267 EUR ha⁻¹, for spruce the same indices are 1644-3272 EUR ha⁻¹, for birch - 683-2188 EUR ha⁻¹.