Scots pine (Pinus sylvestris) is Latvia's most economically important tree species. It accounts for 38% of the total forest area of Latvia. One of diseases affecting P. sylvestris is root rot caused by the fungus Heterobasidion annosum, which causes large economic losses. There is some evidence of Scots pine trees with higher levels of resistance but no absolutely resistant tree clones have been described so far. Many genes encoding peptides and proteins with direct or indirect antifungal activity have been described in various plant species, but only few of them have been studied in conifers. In our study we have utilised various approaches to research genetic aspects of Scots pine resistance to H. annosum. Here we present our initial results. Initially, H. annosum infection was determined in 300 trees and in a subset of twenty seven trees representing fifteen families (progeny of one mother tree) infection levels were quantitatively characterised. Candidate-genes were selected based on previously published research. Gene copy number variation (CNV) analyses were performed on selected samples. Copy number variation polymorphism was detected for a gene encoding a thaumatinlike protein analogues of which are described as potent antifungal proteins in other plants. As increased gene copy number can lead to increased gene product amounts in cells it is possible that an increased copy number of thaumatin-like protein is beneficial to the pine tree in respect to resistance against H. annosum and other pathogens. Further experiments need to be performed to investigate this in more detail.

The effect of growing conditions, age and stocking density on the amount of deadwood in the pine forest stands of Latvia was analyzed in this research. The material for studies was collected within the framework of the National Forest inventory of Latvia in the period 2004 to 2008. From databases of the National forest inventory the data about 1627 sample plots dominated by pine were selected and analysed. The total amount of deadwood (m3 haE-1) was compared among five forest edaphical rows - forests on dry mineral soils, forests on wet mineral soils, forests on wet peat soils, forests on drained mineral soils and forests on drained peat soils. Deadwood was also analysed in five age groups – young, middle age, premature, mature and over-mature stands, as well as in six groups of stocking density – small-density, sparse-density, middle-density, high-density, full-density and over-density stands. It was found out, that the growing conditions (p = 0.000 is less than α = 0.05), stand age (p = 0.000) and stocking density (p = 0.000) have significant influence on the amount of deadwood in pine forest stands. The highest amount of deadwood is in the pine stands on wet mineral soils – 18.6 ± 2.09 m3 haE-1. With increase of the stand age the amount of deadwood also increases and in the mature pine stands the amount of deadwood is 17.8 ± 1.58 m**3 haE-1. The amount of deadwood in the pine forest stands also increases with stocking density and in the over-density stands it is 21.6 ± 2.50 m**3 haE-1.

Large proportion of 30-50 years old spruce stands originated from overstocked plantations can be characterized by low growth potential and present serious problem to forest managers. Although according to legislation unproductive spruce stands can now be clearcut, possible alternative solution allowing a forest owner to remove only trees with the worst growth potential would be also welcome. To be able to recommend any silvicultural measures, information on the inner structural development of the stands is necessary. The aim of this study was to analyze temporal structure of several spruce stands that have originated from overstocked plantations and now belong to the 2nd (increased risk stands) or 3rd (unpromising stands) growth potential groups. Data for the study from seven sample plots located in Forest Research Station ''Kalsnava'' and thinned with different intensity were used. Tree diameter distribution, volume accumulation patterns and tree mortality were analyzed. Correlation between tree diameter and tree diameter difference in the observation period from 2000 to 2006 was weaker than in the observation period from 2006 to 2009, indicating further decline of growth potential. In most cases the major part of the volume was accumulated in the middle of the diameter class distribution. For most of the trees one or both sawlogs were of good or average quality. In order to develop optimal and profitable stand management model, the effect of different thinning methods in spruce stands of low growth potential should be studied in the future.

Experimental self-binding high-density fibreboard is produced of the grey alder (Alnus incana L. Moench) steam-exploded fibres without addition of synthetic adhesives. Milled grey alder chips are processed in steam-explosion unit by saturated steam under pressure of 3.2 MPa at temperature of 235 deg C for 1 min in a 0.5 l batch reactor. The steam-exploded fibres are pressed at 160 deg C temperature under 8 MPa pressure for 10 min in three steps. Properties, such as density, swelling in thickness, water absorption, bending strength, modulus of elasticity at bending, and internal bonding strength of the studied fibreboard samples are reported. Differences between the raw milled chippings and the exploded fibres are observed by scanning electron microscope. The study is focused on modified technical options of the steam-explosion unit supplied with two containers receiving different kinds of the exploded biomass farther used to obtain the hot-pressed boards. The cascade of the receivers is explained in a presently pending patent. The self-binding high-density fibreboard samples show the following properties comparable to commercial products: density of at least 1.35 g cmE-3, moisture content of 7.2%, swelling in thickness of 8.1%, water absorption of 3.2%, bending strength of 27 N mmE-2, modulus of elasticity of 6,259 N mmE-2, and internal bonding of 0.92 N mmE-2.

Black alder wood is suitable for production of high quality veneer and other uses, but doe to its small share in total forest area (3%) in Latvia its genetic improvement have not been a priority. Set of progeny tests, together 22.8 ha, have been established only in the last decade. First of them have reached the age of 8 to 10 years and are suitable for first assessment. Aim of our study was to evaluate potential of improvement of black alder using selection, based on progeny testing. Data from 4 open pollinated progeny tests of phenotypically selected black alder plus trees, located in central part of Latvia, each containing from 15 to 21 families, are evaluated, using breeding value as a criterion. Results reveal that selection of parent trees with the practically possible intensity (10%) yields notable improvement in height at the age of 8 to 10 years: from 10 to 32%. Parent trees of open-pollinated families S9, S14, S16 and 84115 that have superior productivity and above-average quality can be recommended for establishment of second-round seed orchard. Estimates of genetic parameter suggest that selection in black alder trials could be carried out with high accuracy and improvements are possible both in productivity and quality (branch thickness, stem straightness, occurrence of spike knots).

The study was conducted to estimate the economic values (EV) of Begait cattle breeding-objective traits and their effects on the returns to investment in breeding programs using bio-economic model. Production systems were described according to their level of input and sale age, namely, low input herd management (LIHM) and medium input herd management (MIHM) based on fixed herd size for genetic improvement of multiple traits. Results showed that all considered traits have positive economic values across production systems except pre weaning daily body weight gain (PrDG). However, production systems had significant influence on the magnitude of EV of traits. The MIHM was superior by 100 to 9% to the LIHM system. Regardless of the two production systems, calving interval (CI) had the highest EV followed by dressing percentage (DP) and mature weight (MWT). Although, the overall change of beef trait EV influenced the marginal profit through price and production variable changes at constant MY, the more sensitive change was observed with the changes of MY EV. Traits of milk yield had 1 to 12% increment on profit with 1 to10% improvement in its EV by rising milk price, reduced weaning and reduced culling rates. However, beef traits only made 5.1×10-7 to 2.3×10 -6% raises on profits with 18 to 50% increment in its EV by beef price increment and reduced age at first calving. The higher increments of profit parallel to the EV of milk production trait and mostly simultaneous improvements on CI have a great indication to give priorities on milk yield traits than beef traits in any Begait cattle improvement program. Therefore, improving milk production traits and fecundity traits simultaneously with their market outlet is better to increase the profitability of farmers and sustains the valuable breed in their habitat.

A survey of marketing system, socio economic role and intra household dynamics of indigenous chicken was conducted in Gomma Wereda located at 390 km southwest of Addis Ababa. Six Kebeles of the Wereda were randomly identified and 30 households (hh) randomly selected from each kebele were used to collect data on the profile of the respondents, chicken population and flock structure, marketing system, socio economic role and intra household dynamics of the indigenous chicken using questionnaire, regular visit and target group discussions. The results obtained showed that the mean flock size/hh of the study area (6.23 chickens) was greater than that of the national average (4.1) and strangely dominated by hens of > 5 months of age. Informal and open markets of live birds and eggs are common throughout the Wereda. There is variation in market price of chickens and eggs attributed to the physical condition of the birds, disease outbreak, time of incubation, and holidays and festivals. Both eggs and chickens pass through different individuals before reaching consumers and about 52.2% of the market chickens and eggs are collected and transported by retailers to terminal markets contributing to disease spread and quality deterioration. About 96.7% of the ownership of chicken was held by women and with the exception of poultry house construction all the other activities including marketing are done by women indicating that village chickens are source of self-reliance for women. There are no taboos connected to consumption of poultry. And yet, chickens and eggs are not among staple food items in the Gomma Wereda. The results obtained also showed that lack of access to credit and high prevalence of disease conditions and predators are the major constraints to improve household poultry in the study area.

Icing notably increases the mass of a tree crown, causing damage to the tree. So far, a very limited number of studies have assessed the icing influence on coniferous trees, none of them in Latvia. The aim of the study was to assess the influence of tree parameters and recent thinning on the proportion of damaged trees and the type of damage in Scots pine stands. The study sites were located in the eastern part of Latvia, damaged in December 2012. In total, 98 pine dominated stands of different age were selected randomly. Eight (mean) plots per stand were established; in each plot, all trees larger than 2.1 cm were measured and the type of damage assessed. The above-ground biomass from 12 randomly selected stands (57 dominant trees) of different age was weighted with and without icing. The biomass of pine with icing exceeded that without 1.5 ± 0.27 times. The mean proportion of damaged trees in pine dominated stands was 26%; the proportion of broken trees peaked in the middle-aged stands (41 – 70 years old), but the largest proportion of pooled bent and uprooted trees was found in the young (11 – 20 years old) stands. The proportion of damaged dominant trees was affected by the slenderness coefficient – a higher proportion of such trees was found among more slender trees. The results suggest that the risk of icing damage could be reduced by silvicultural measures boosting individual tree stability.

Climatic changes are shifting the potential tree distribution limits of many tree species northwards. One of such species is Fagus sylvatica, currently represented in Latvia only by a few stands. In order to increase knowledge on its potential use in the forest management, the aim of our study was to characterize the growth of beech in a young stand in the central part of Latvia. The stand of beech and spruce, mixed in rows with an initial spacing of 2.5 x 2.5 m in Oxalidosa forest type was assessed. Survival of European beech in clear cutting was similar to that observed for the native Norway spruce (73% and 79%, respectively), but both height and diameter were notably and significantly superior for wildlings at the mean age of 15 ± 2 years, reaching on average 7.4 ± 0.30 m and 8.9 ± 0.69 cm, respectively. Increasing ring width with increasing tree age for both tree species was observed until the last four years, when large and increasing superiority of beech over spruce, coinciding with reduction of ring width of spruce, was noted. It was most likely caused by intensified competition due to very wide crowns formed by young beech trees in the plantation with wide spacing: average crown radius reached 2.4 ± 0.16 m, for few trees exceeding even 4 m.

Recent studies have demonstrated the occurrence of different needle cast (Lophodermium spp.) species in young Scots pine Pinus sylvestris L. stands in different regions of Latvia. The impact of these fungi has been known also historically, but is predicted to increase in future due to climate changes that are forecasted to have a positive impact on presence and vigour of various species of fungi. The aim of the study was to characterize the needle cast damage in young Scots pine stands in central Latvia. Material was collected in 12 Scots pine stands at the age of 3 to 26 years in 28 plots with a total area of 8.1 ha in the middle of two consecutive growing seasons (years 2012 and 2013). The impact of disease was visually assessed using a 5 grade scale, depending on the proportion of damaged (brown) one-year old needles. Incidence of damaged trees (P, %) and damage intensity (R, %) was calculated and used to characterize the occurrence and severity of the infection in the stands as well as its link to other stand parameters. Damage incidence (ranging from 20 to 100%), as well as the intensity (from 4 to 35%) was slightly (incidence-also significantly) higher in 2013 in comparison to 2012; correlation between those two parameters was strong in both years (r = 0.94 and r = 0.84, respectively). The stand age, density (ranging from 1200 to 6900 trees haE-1) and tree height did not significantly correlate with the damage incidence or intensity. Forest type (Hylocomiosa or Myrtillosa mel.) was not a significant factor, too.