Dagnija Lazdina

Influence of spot mounding on height growth and tending of Norway spruce: case study in Latvia

Abstract Norway spruce is commonly regenerated by planting and disc trenching is by far the most widely used soil preparation method in Latvia; however, in specific site conditions other methods might be beneficial. Therefore aim of our study was to assess influence of spot mounding on early growth and tending of Norway spruce in hemiboreal forests. Spot mounding was compared with disc trenching or no soil preparation in central part of Latvia (57° N 24° E) in five different forest types, where two-year-old containerized Norway spruce seedlings were planted. Influence of soil preparation method on tending was assessed in the same region in two different sites in a single forest type on drained fertile mineral soil. Spot mounding had positive effect on the height increment of the dominant trees at the 6th to 8th growing season. Mean height of Norway spruce at the end of 8th growing season on mounds significantly exceeded that on unprepared soil: 179 ± 6.5 and 152 ± 6.2 cm, respectively. Similarly mean height on mounds was significantly larger than on furrows: 209 ± 3.9 and 154 ± 4.0 cm, respectively. Projective vegetation cover before the tending was significantly higher in spot-mounded, but after - in disc trenched sites. Networking time for brashsaw operators in spot-mounded (478 min/ha-1) and disc trenched (462 min/ha-1) sites was similar (p > 0.05). Overall, spot mounding ensured more suitable microenvironment resulting in higher productivity of planted trees and had no negative effect on quality or efficiency of tending, therefore its wider use is recommended.

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

Abstract 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.