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Silva Fennica 1926-1997
Acta Forestalia Fennica

Silva Fennica vol. 34 no. 1 | 2000

Category: Research article

article id 645, category Research article
Veli-Pekka Heikkinen & Antti Kanto. (2000). Market model with long-term effects – empirical evidence from Finnish forestry returns. Silva Fennica vol. 34 no. 1 article id 645.
The aim of the study is to reformulate the conventional market model by considering also long-run characteristics of forestry returns. Finnish stumpage prices and the stock market index are found co-integrated. Co-integration relationship between timber and stock market indicates that there are factors in timber market like high transaction costs, illiquidity or temporal lack of information, and in the Finnish case, price recommendations that are priced by market. The presence of long-run effects may make the short-term market model mis-specified and it may give misleading and incomplete results concerning the expected risk and return of forestry. In our case, the market model risk beta was only slightly biased. This study indicates that an error-correction model is more appropriate model than the market model.
  • Heikkinen, Helsinki School of Economics, P.O. Box 1210, FIN-00101 Helsinki, Finland ORCID ID:E-mail: (email)
  • Kanto, Helsinki School of Economics, P.O. Box 1210, FIN-00101 Helsinki, Finland ORCID ID:E-mail:
article id 644, category Research article
Jouni Pykäläinen. (2000). Defining forest owner’s forest-management goals by means of a thematic interview in interactive forest planning. Silva Fennica vol. 34 no. 1 article id 644.
Numerical optimization may not be the best way to launch an interactive planning process. The forest owner may not be able to identify precise management goals, as required in numerical optimization, for his forest. The owner may also think that it is impossible to express forest-management goals numerically. Due to these reasons, thematic interview was tested as an introductory method in interactive planning in several actual planning cases. It was observed that these interviews helped the owners in outlining their forest-management goals, and they offered an appropriate framework for defining these goals. It was also noticed that the goals defined in the course of the interviews could be included in the planning model in a way understood and accepted by the owners, and the goals defined could be fulfilled.
  • Pykäläinen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail: (email)
article id 643, category Research article
Pekka Eskelinen & Harri Eskelinen. (2000). A K-band microwave measuring system for the analysis of tree stems. Silva Fennica vol. 34 no. 1 article id 643.
The internal structure of growing trees and freshly cut logs can be characterized in real time by analysing the transmission and reflection of Ku- or K-band microwave energy injected with a horizontal polarization towards the material. Information about the moisture content, material bends, number and location of knots and sections of spoiled wood e.g. due to insects can be gathered in real time. Most sensitive test parameters are attenuation, group delay and the rotation of a linearly polarized wavefront. A simultaneous recording of reflection reduces errors caused by non-significant surface deformations. The spatial resolution, humidity equalization and noise immunity can be improved by applying a wideband frequency modulation. Commercial building blocks supplemented with a special antenna arrangement give possibilities also for the rough harvester environment.
  • Eskelinen, Lappeenranta University of Technology, Department of Electrical Engineering, P.O. Box 20, FIN-53851 Lappeenranta, Finland ORCID ID:E-mail: (email)
  • Eskelinen, Lappeenranta University of Technology, Department of Electrical Engineering, P.O. Box 20, FIN-53851 Lappeenranta, Finland ORCID ID:E-mail:
article id 642, category Research article
Jonas Rönnberg. (2000). Logging operation damage to roots of clear-felled Picea abies and subsequent spore infection by Heterobasidion annosum. Silva Fennica vol. 34 no. 1 article id 642.
Two studies were carried out to examine the effects of clear-felling operations on stump roots of Norway spruce (Picea abies (L.) Karst.). In study I, the number of cases and the degree of damage to stump roots of Norway spruce were investigated on three clear-felled sites in northern and southern Sweden respectively. The cutting was done in winter or spring. A mean of 37% of the stumps had signs of root damage caused by clear-felling operations. Study II was carried out on two sites in southern and two sites in northern Sweden. The trees were clear-felled in June or July. The frequency of natural infection by Heterobasidion annosum (Fr.) Bref. through damaged roots was compared to infection through stump surfaces. The total area of damage on roots was 88% of the stump surface area. On average, 54% of the stumps were infected through the stump surface and 19% through locations of root damage. The root infections, however, were generally small in size as compared to stump surface infections. The study shows that damage to roots at clear-felling may be extensive, but this probably is not of great importance for the efficacy of stump treatment against H. annosum.
  • Rönnberg, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: (email)
article id 641, category Research article
Juha Kaitera. (2000). Analysis of Cronartium flaccidum lesion development on pole-stage Scots pines. Silva Fennica vol. 34 no. 1 article id 641.
Historical and current lesion development and sporulation of Cronartium flaccidum was investigated in a stand of artificially seeded pole-stage Pinus sylvestris in northern Finland. An average of 6.5 lesions developed per infected tree, most of them occurring on a minority (25%) of the trees. During the monitoring period of five years, fresh aecia appeared mainly in 7–10-year-old shoots, the age of the shoots bearing aecia varying between 3–20 years. Aecia appeared for the first time most frequently in 5–10-year-old shoots. Infection waves occurred, whereas lesions were formed most frequently in shoots formed in various years through the 1980s. After the lesions started to sporulate, sporulation in most lesions that finished sporulating during the monitoring period lasted for 1–2 years. The aecia in between 47% and 59% of the infected shoots developed annually over a longer length in proximal direction than in distal direction next to the previous year’s infection. The aecia-bearing distal part of the shoot was longer in between 19% and 37% of the shoots.
  • Kaitera, Finnish Forest Research Institute, Rovaniemi Research Station, P.O. Box 16, FIN-96301 Rovaniemi, Finland ORCID ID:E-mail: (email)
article id 640, category Research article
Jarkko Koskela. (2000). A process-based growth model for the grass stage pine seedlings. Silva Fennica vol. 34 no. 1 article id 640.
A carbon- and nitrogen-balance model, applying pipe model theory and a modification of functional balance as growth-guiding rules, is presented for the grass stage pine seedlings. Three populations of Pinus merkusii Jungh. et de Vriese, originating from northern and northeastern Thailand, were grown under controlled environment for 47 weeks to obtain parameter information, to evaluate the model performance and to investigate genotypic variation in various characteristics among the populations. Monte Carlo simulations were used to evaluate the sensitivity of the model behaviour to varying parameter values and to calibrate the model for each population. With given sets of parameter values, the simulated biomass development fitted rather well the observed one during the experiment. The two most important parameters determining model performance were within-shoot shading and specific nitrogen uptake rate of fine roots. The fit of simulated versus measured fine roots had a major effect on acceptable model performance in Monte Carlo simulations. Significant variation in biomass growth, nitrogen use efficiency, height, stem diameter, total carbon concentrations of stem and fine roots, and total nitrogen concentrations of needles, transport roots and fine roots was found among the populations. The observed genotypic variation in seedling biomass and stem diameter was consistent with the geographical distribution of the populations while the variation in the rest of the measured characteristics was not. It seems that P. merkusii populations in Thailand are adapted to more site specific conditions rather than climatic conditions alone, and that the variation in biomass growth may result from variation in internal carbon and nitrogen dynamics among the populations.
  • Koskela, Department of Forest Ecology/Tropical Silviculture Unit, P.O. Box 28, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: (email)

Category: Research note

article id 646, category Research note
K. S. Krishna Chaitanya, S. Keshavkant & S. C. Naithani. (2000). Changes in total protein and protease activity in dehydrating recalcitrant sal (Shorea robusta) seeds. Silva Fennica vol. 34 no. 1 article id 646.
A rapid loss of viability was recorded in sal seeds when dehydrated below 36.7% moisture content, at ambient conditions. Seed becomes non-viable at 6 days after harvest (dah). Gradual decline in total protein content due to corresponding increase in protease activity preceded loss of viability. Almost 43.7% and 52.6% loss in total protein content was observed on 3 dah in embryonic axis and cotyledon respectively of seeds showing 100% viability. No protease activity was detected in the embryonic axis and cotyledon of freshly harvested viable seeds (0 dah). The protease activity was detected after 12 hrs of storage and increased sharply with peak levels on 6 dah (0.71 ± 0.04 / min/mg protein) and 4 dah (0.16 ± 0.01 / min/mg protein) in embryonic axis and cotyledon respectively. Later on the enzyme activity declined sharply in both the tissues. Enhanced protease activity in embryonic axes and cotyledons has been discussed with corresponding decline in total protein during desiccation induced loss of viability in sal seeds.
  • Chaitanya, Pt. Ravishankar Shukla University, Seed Biology Lab, School of Life Sciences, Raipur – 492 010 (M.P.), India ORCID ID:E-mail:
  • Keshavkant, Pt. Ravishankar Shukla University, Seed Biology Lab, School of Life Sciences, Raipur – 492 010 (M.P.), India ORCID ID:E-mail:
  • Naithani, Pt. Ravishankar Shukla University, Seed Biology Lab, School of Life Sciences, Raipur – 492 010 (M.P.), India ORCID ID:E-mail: (email)

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