Daugaviete, M. 2011. Above-Ground Biomass in Young Grey Alder (Alnus incana [L.] Moench.) Stands.  Baltic Forestry 17 (1): 76-82

Presented is a method for estimating the amount of leafless naturally moist above-ground biomass in one-to-five-year-old untended naturally grey alder regenerating stands with the respective values calculated by using easy-to-measure stand parameters like the average height and the number of stems (root suckers, stool shoots, coppice, or saplings) per unit area. An equation is proposed for estimating the amount of biomass in one-to-five-year-old grey alder growth: biomass (M) is calculated as a function of the average stem height (H_V) and the number of stems (N) per ha: M = 0.0536·H_V2.2516·N,(R²= 0.905; P<0.05).
The biomass of untended young grey alder stands is calculated from the average stem height of H_V =0.8-4.8 m in one-year-old and five-year-old stands, respectively, with the number of stems per 1 ha ranging from 10,000 to 100,000.
The calculations show that, with the average stem height in one-to-five-year-old grey alder stands increasing only by 0.1m, the amount of above-ground biomass increases by an average of 30%, provided the number of stems per ha is the same; in case the number of stems is by 10,000 larger, the biomass increase is by 40%.
The research shows that the amount of naturally moist biomass in one-to-five-year-old untended grey alder stands is uneven with the variations depending on stand age and stem dimensions.
The amount of biomass in untended grey alder stands depending on the stand density varies in a fairly wide range: from 0.9 t·ha⁻¹ to 7.7 t·ha⁻¹ ha in one-year-old stands; from 2.2 t ha⁻¹ to 23.6 t·ha⁻¹ in two-year-old stands; from 5.2 t·ha⁻¹ to 28.9 t·ha⁻¹ in three-year-old stands; from 7.3 t·ha⁻¹ to 57.4 t·ha⁻¹ four-year-old stands; from 15.2 t·ha⁻¹ to 64.4 t·ha⁻¹ per ha in five-year-old stands.

Key words: grey alder, biomass, average height, number of stems per ha, natural regeneration, coppice, saplings

Luostarinen, K. 2011. Density, Annual Growth and Proportions of Types of Wood of Planted Fast Grown Siberian Larch (Larix sibirica) Trees.  Baltic Forestry 17 (1): 58-67

Siberian larch (Larix sibirica Ledeb.) is widely cultivated in Finland as it thrives very well and grows rapidly on fertile sites in the country. As rapid growth affects the wood properties, particularly in softwoods, it is not clear that these fast growing trees would produce raw material of similar quality as trees grown in their native areas. Thus, in this study the proportion of wood types (juvenile wood, mature heartwood, and sapwood) was quantified at three different heights up the trunk (butt end, 4.5 and 9.0 m) in Siberian larch trees cultivated in Finland. Additionally, density and annual growth patterns were studied in the three wood types at the respective heights. The wood located at the butt differed in some respects from the wood located higher up the trunk, but particularly wood density and the proportion of latewood (LW%), important for the mechanical properties, stayed similar up to 4.5 m of height. Thus the lower part of the trunks, also containing the smallest proportion of juvenile wood, seems to be most suitable for structural use. The effect of extractive content on the density is emphasised, as many of the observed correlations were different in mature heartwood and sapwood. Radial density differences are larger in Siberian larch wood grown in Finland than in Siberia, which emphasises the poorer quality of juvenile wood of fast grown planted trees.

Key words: earlywood, juvenile wood, latewood, mature heartwood, proportion of latewood, ring width, sapwood

Daugavietis, M., Bisenieks, J. and Daugaviete, M. 2011. Interrelations among Grey Alder Stand Characteristics.  Baltic Forestry 17 (1): 68 – 75

The purpose of the study is to determine the interrelations of the assessment characteristics necessary for modelling the yield of grey alder stands. The models serve as a theoretical base that allows developing recommendations for forest cultivation technologies in line with the forest cultivation goals. The growth and yield tables for three site indexes, which have been used in forest management until now, do not encompass the whole variety of grey alder stands, so possibilities of expanding the tables are being looked for by introducing additional site indexes by means of extrapolation.
A new mathematical model for determination of grey alder site index has been developed on the basis of data obtained from stem analysis of sample tree trunks, which can be used to calculate curves of growth of the average height up to age 40, and a new scale for determination of the site index has been recommended, where site index is denoted as the average height of the stand in metres at age 20. The method of multiple regression has been used for interpretation of interrelations of stand assessment characteristics. The regression models incorporate three independent variables selected by way of logical analysis. The calculation of the regression coefficients uses data obtained from a one-time survey of 150 sample plots. A description of the sample plots is provided. Formulas of I. Liepa have been used for calculation of stem volume and current increment of the reduced volume of the stand. Mathematical models of the interrelations of stand assessment characteristics have been developed, which can be used to determine the following stand yield characteristics: average diameter, basal area, volume, the reduced actual volume increment and the current annual height increment.
It has been demonstrated that grey alder stands up to age 40 maintain a high yield and large annual current volume increment, which is higher than the average volume increment.
In the models, one of the main independent variables that can be regulated with forest management is the number of trees, and the models allow predicting the effect of thinning on the wood yield.

Key words: grey alder, site index, volume, the reduced current volume increment, current increment of average height, current increment of average diameter at breast height

Spinelli, R. and Magagnotti, N. 2011. Strategies for the Processing of Tree Tops from Hybrid Poplar Plantations.  Baltic Forestry 17 (1): 50-57

Industrial poplar plantations represent a strategic source of wood products for many countries. Harvested after 10 to 30 years, they yield about 200 t ha⁻¹ of timber and 100 t ha⁻¹ industrial wood. The latter is obtained from poplar tops, which can be converted into chips, or a mix of pulpwood and chips. The study compared four options to process poplar tops. Alternatives derived from the intersection of two product strategies (pulpwood and chips, or chips only) with two pulpwood processing methods (manual or mechanized). Both mechanization and simplification (only one product) succeeded in reducing production cost, but the former had a stronger effect. The tests demonstrated that all options were cost-effective and could return some profits. However, the exclusive production of chips offered lower profits, compared to an articulate product strategy aimed at maximising value recovery. In the case of Italian poplar plantations, the price difference between pulp and chips is generally larger than the cost reduction obtained with integral chipping. Similar conclusions were reached by other authors working with spruce and beech in Central Europe. Of course, this is only true for the current price levels of pulpwood and chips: results may change, if this price balance will be altered by the growing demand for biomass fuel.

Key words: biomass, poplar, plantation, mechanization