Possibilities of competition indices to describe competitive differences between Scots pine families.

Possibilities of distance-independent and -dependent competition indices to describe the competition stress of an individual tree was studied in southern Finland. Five half-sib open-pollinated families and one check lot of Scots pine (Pinus sylvestris L.) was used as study material in order to analyse competitive interactions of crown form and stand density variation. Almost all competition indices correlated strongly with radial increment. Thus distance-independent indices were adequate to describe competition in young row plantations, where distance effects between trees were implicitly eliminated. Correlations between indices and height increment were not significant. Along with the increase in competition, the width and length of the crown and the diameter increment of the stem of some narrow-crowned families decreased slowly compared to wide-crowned families

Oikeusministeriön hallinnonalan tuottavuusohjelma

Julkaisu sisältää oikeusministeriön hallinnonalan tuottavuusohjelman vuosille 2006-11. Ohjelma on valmisteltu hallituksen kehyspäätöksessä 11.3.2005 esitettyjen linjausten ja valtiovarainministeriön antamien valmisteluohjeiden pohjalta. Ohjelma sisältää oikeusministeriön hallinnonalan yleisten lähtökohtien ja tuottavuustavoitteiden sekä keskeisten lähivuosien tuottavuushankkeiden ja –toimenpiteiden tarkastelun ja vaikutusten arvioinnin. Tuottavuusohjelma on toimitettu valtiovarainministeriölle ja edelleen hallituksen käsittelyä varten

Geographical patterns in the radial growth response of Norway spruce provenances to climatic variation

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Investigating thermal properties of gas-filled planetary regoliths using a thermal probe

We introduce a general purpose penetrator, fitted with a heater, for measuring temperature and thermal diffusivity. Due to its simplicity of deployment and operation the penetrator is well suited for remote deployment by spacecraft into a planetary regolith. Thermal measurements in planetary regoliths are required to determine the surface energy balance and to measure their thermal properties. If the regolith is on a planet with an atmosphere a good understanding of the role of convection is required to properly interpret the measurements. This could also help to identify the significant heat and mass exchange mechanisms between the regolith and the atmosphere. To understand the role of convection in our regolith analogues we use a network of temperature sensors placed in the target. In practical applications a penetrator will push material out of the way as it enters a target possible changing its thermal properties. To investigate this effect a custom built test rig, that precisely controls and monitors the motion of the penetrator, is used. The thermal diffusivity of limestone powder and sand is derived by fitting a numerical thermal model to the temperature measurements. Convection seems to play an important role in the transfer of heat in this case. Firstly a diffusion-convection model fits the laboratory data better than a diffusivity-only model. Also the diffusivity derived from a diffusivity-convection model was found to be in good agreement with diffusivity derived using other methods published in the literature. Thermal diffusivity measurements, inspection of the horizontal temperature profiles and visual observations suggests that limestone powder is compacted more readily than sand during entry of the penetrator into the target. For both regolith analogues the disturbance of material around the penetrator was determined to have an insignificant effect on the diffusivity measurements in this case

Ikä vaikuttaa kuusen kuolleisuuteen

Ikääntyminen ja kilpailu heikentävät puiden veden ja ravinteiden saantia, joka altistaa ne kuolemiselle. Joissakin tutkimuksissa kuusen eloonjäämisen on havaittu laskevan suurissa läpimittaluokissa, mutta iän vaikutusta ei ole otettu huomioon. Tässä tutkimuksessa tarkasteltiin kuusen ikääntymisen vaikutusta eloonjäämiseen sovittamalla useita vaihtoehtoisia eloonjäämismalleja

Separating water-potential induced swelling and shrinking from measured radial stem variations reveals a cambial growth and osmotic concentration signal

The quantification of cambial growth over short time periods has been hampered by problems to discern between growth and the swelling and shrinking of a tree stem. This paper presents a model, which separates cambial growth and reversible water-potential induced diurnal changes from simultaneously measured whole stem and xylem radial variations, from field-measured Scots pine trees in Finland. The modelled growth, which includes osmotic concentration changes, was compared with (direct) dendrometer measurements and microcore samples. In addition, the relationship of modelled growth and dendrometer measurements to environmental factors was analysed. The results showed that the water-potential induced changes of tree radius were successfully separated from stem growth. Daily growth predicted by the model exhibited a high correlation with the modelled daily changes of osmotic concentration in phloem, and a temperature dependency in early summer. Late-summer growth saw higher dependency on water availability and temperature. Evaluation of the model against dendrometer measurements showed that the latter masked a true environmental signal in stem growth due to water-potential induced changes. The model provides better understanding of radial growth physiology and offers potential to examine growth dynamics and changes due to osmotic concentration, and how the environment affects growth.Peer reviewe

Soil frost affects stem diameter growth of Norway spruce with delay

Soil temperature and soil frost intensity are affected by the depth of insulating snow cover and the timing of snowmelt which are predicted to change by climate warming. This may increase tree growth if there is less soil freezing or decrease growth if there is no insulating snow cover, but frost temperatures still exist. Previously, we showed that the changes in soil frost by snow manipulations in a ~50-year-old stand of Norway spruce (Picea abies (L.) Karst.) in eastern Finland in two winters (2005/2006 and 2006/2007) led to short-term changes in physiology, morphology, and the growth of the shoots and roots. The treatments were: (i) control with natural insulating snow accumulation and melting; (ii) snow removal during winter; and (iii) snow removal in winter and insulation at the top of the forest floor in late winter to delay soil thawing. In this study, we examined lagged effects of those treatments by radial trunk increment cores during the nine-year recovery period after the termination of the treatments. Annual ring width index (AWI) was calculated for each year by normalization of the ring width in the respective year in proportion to the ring width in the last year (2005) before the treatments. No differences in AWI were found between the treatments before or during the snow manipulation period. However, differences started to appear one year after the treatments were finished, became significant four years later in 2011 and lasted for three years. The radial increment was lower in the treatment with snow removed than in the control and in the treatment with insulation to delay soil thawing, but there were no differences between the latter two treatments. The results indicate that a lack of snow cover may not only have short-term impacts but longer-lasting consequences on the radial growth of trees. The positive effects of prolonged growing season by the increasing summer temperatures on forest growth predicted for the boreal region may therefore not be fully realised due to the negative effects of decreased snow cover and increasing soil freezing