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Silva Fennica vol. 47 no. 2 | 2013

Category : Research article

article id 963, category Research article

Szymon Bijak, Michał Zasada, Agnieszka Bronisz, Karol Bronisz, Maciej Czajkowski, Łukasz Ludwisiak, Robert Tomusiak, Rafał Wojtan. (2013). Estimating coarse roots biomass in young silver birch stands on post-agricultural lands in central Poland. Silva Fennica vol. 47 no. 2 article id 963. https://doi.org/10.14214/sf.963

Keywords: abandoned farmland; belowground biomass; allometric equations; root-to-shoot ratio

Highlights: Age and size of the tree are the most important factors that influence the amount of belowground biomass; Allocation of the biomass to the coarse roots also depends on age and size of the tree

Abstract | Full text in HTML | Full text in PDF | Author Info

Study analyses coarse (d>2 mm of diameter) roots biomass dynamics in young succession stands of silver birch (Betula pendula Roth) growing on abandoned farmlands in central Poland. Research material based on 181 sample trees, which were gathered in 20 pure silver birch stands in 5 locations. The age of the trees varied from 1 to 16 years. Coarse roots biomass of the investigated trees ranged from 0.7 to 4305.5 g/tree (422.6 g/tree on average) showing great variability (coefficient of variation equals 185%). A clear dependence of belowground biomass on the age and size of a tree was observed. Root-to-shoot ratio values vary from 0.1 to 1.0 with evidence of a tendency to decrease with increasing age, diameter at the breast height and height of analysed trees. An allometric equation was elaborated for the estimation of belowground biomass based on height or diameter at breast height of young silver birches. The suitability of this formula should be considered for the estimation of biomass accumulation and carbon sequestration by young successional silver birch stands growing on abandoned agricultural lands.

Bijak, Warsaw University of Life Sciences – SGGW, Faculty of Forestry, Laboratory of Dendrometry and Forest Productivity, Nowoursynowska 159, 02-776 Warszawa, Poland E-mail: szymon.bijak@wl.sggw.pl
Zasada, Warsaw University of Life Sciences – SGGW, Faculty of Forestry, Laboratory of Dendrometry and Forest Productivity, Nowoursynowska 159, 02-767 Warszawa, Poland E-mail: michal.zasada@wl.sggw.pl
Bronisz, Warsaw University of Life Sciences – SGGW, Faculty of Forestry, Laboratory of Dendrometry and Forest Productivity, Warszawa, Poland E-mail: agnieszka.bronisz@wl.sggw.pl
Bronisz, Warsaw University of Life Sciences – SGGW, Faculty of Forestry, Laboratory of Dendrometry and Forest Productivity, Warszawa, Poland E-mail: karol.bronisz@wl.sggw.pl
Czajkowski, Warsaw University of Life Sciences – SGGW, Faculty of Forestry, Laboratory of Dendrometry and Forest Productivity, Warszawa, Poland E-mail: maciej.czajkowski@wl.sggw.pl
Ludwisiak, Warsaw University of Life Sciences – SGGW, Faculty of Forestry, Laboratory of Dendrometry and Forest Productivity, Warszawa, Poland E-mail: lukasz.ludwisiak@wl.sggw.pl
Tomusiak, Warsaw University of Life Sciences – SGGW, Faculty of Forestry, Laboratory of Dendrometry and Forest Productivity, Warszawa, Poland E-mail: robert.tomusiak@wl.sggw.pl
Wojtan, Warsaw University of Life Sciences – SGGW, Faculty of Forestry, Laboratory of Dendrometry and Forest Productivity, Warszawa, Poland E-mail: rafal.wojtan@wl.sggw.pl

article id 958, category Research article

Back Tomas Ersson, Linus Jundén, Urban Bergsten, Martin Servin. (2013). Simulated productivity of one- and two-armed tree planting machines. Silva Fennica vol. 47 no. 2 article id 958. https://doi.org/10.14214/sf.958

Keywords: discrete-event simulation; mechanized planting; forestry; silviculture; automation; terrain model; root model

Highlights: Using discrete-event simulation and detailed terrain and machine models, the productivities of excavator-based one- and two-armed tree planting machines were simulated; The machines’ arms were equipped with one-and two-headed planting devices; Two planting heads per arm rather than two arms per base machine is better for increasing the productivity of intermittently advancing planting machines on Nordic clearcuts.

Abstract | Full text in HTML | Full text in PDF | Author Info

To increase mechanized planting, planting machine productivity must increase in order to improve cost-efficiency. To determine if excavators with two crane arms could potentially help to increase planting machine productivity under Nordic clearcut conditions, we modelled one-armed and semi-automated two-armed excavators with one- and two-headed planting devices. Using a recently developed tool for discrete-event simulation, these machine models then mounded and planted seedlings on terrain models with moraine soil having various frequencies of obstacles (stumps, roots and stones). Compared to if the two heads were mounted pairwise on only one arm, the results showed that productivity did not increase if two planting heads were attached individually to two separate crane arms. But productivity did increase if the planting machine had four planting heads mounted pairwise on two separate arms. However, despite assuming automated mounding and crane motion between planting spots, the two-armed, four-headed model never achieved high enough productivity levels to make it more cost-efficient than one-armed machines. The simulations illustrate that our terrain models generate realistic root architecture and boulder content distributions in moraine soil, while our machine models functionally describe mechanized planting work. Based on our assumptions, we conclude that further development work on two-armed excavator-based planting machines for Nordic clearcut conditions is not warranted. Our simulations reveal that increasing the number of planting heads per crane arm rather than number of crane arms per base machine offers the greatest potential to raise the productivity of intermittently advancing planting machines.

Ersson, Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology, SE-901 83 Umeå, Sweden E-mail: back.tomas.ersson@slu.se
Jundén, UMIT Research Lab, Umeå University, SE-901 87 Umeå, Sweden E-mail: linus.junden@gmail.com
Bergsten, Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology, SE-901 83 Umeå, Sweden E-mail: urban.bergsten@slu.se
Servin, UMIT Research Lab, Umeå University, SE-901 87 Umeå, Sweden E-mail: martin.servin@physics.umu.se

article id 956, category Research article

Michał Zasada. (2013). Evaluation of the double normal distribution for tree diameter distribution modeling. Silva Fennica vol. 47 no. 2 article id 956. https://doi.org/10.14214/sf.956

Keywords: diameter distribution; simulated annealing; goodness-of-fit; Weibull distribution; maximum likelihood method; method of moments

Abstract | Full text in HTML | Full text in PDF | Author Info

The double normal distribution consists of two normal distributions truncated at their means and then combined in such a way, that points of truncation now become the overall distribution mode. So far, parameters of the double normal distribution have been estimated exclusively using the method of moments. This study evaluates the maximum likelihood method for the estimation of the double normal distribution parameters in Scots pine stands in Poland, and compares it to the results of the method of moments and the two-parameter Weibull distribution fitted using the maximum likelihood method and the method of moments. Presented results show that it is not recommended to use the maximum likelihood method of parameter fitting with Nelder-Mead and quasi-Newton optimization algorithms for the double normal distribution for small samples. However, it can be used for large samples, giving the fit comparable to the two-parameter Weibull distribution and providing parameters having sound practical and biological meaning. In the case of smaller samples for the double normal distribution it is recommended to apply the maximum likelihood method with the alternative simulated annealing optimization algorithm, use the method of moments or substitute the described distribution with more the flexible and robust Weibull distribution. For the smaller samples, the method of moments was superior to the maximum likelihood method.

Zasada, Warsaw University of Life Sciences, Faculty of Forestry, Laboratory of Dendrometry and Forest Productivity, Nowoursynowska 159, 02-776 Warsaw, Poland E-mail: michal.zasada@wl.sggw.pl

article id 954, category Research article

Anna-Maria Eriksson, Jörgen Olsson, Bengt Gunnar Jonsson, Sara Toivanen, Mattias Edman. (2013). Effects of restoration fire on dead wood heterogeneity and availability in three Pinus sylvestris forests in Sweden. Silva Fennica vol. 47 no. 2 article id 954. https://doi.org/10.14214/sf.954

Keywords: Scots pine; CWD; prescribed burning; decay stage; charred wood

Abstract | Full text in HTML | Full text in PDF | Author Info

Restoration fires are increasingly used as a conservation tool in Sweden to recreate forests with characteristics of previous forests that were periodically disturbed by fires and promote fire-dependent species. Restoration fires can result in large inputs of fresh dead wood, but there are risks of losing some of the existing, pre-fire dead wood. To assess these counteracting effects we studied the heterogeneity and availability of dead wood before and after three restoration fires in boreal Scots pine forests. Specifically, we studied volumes of stumps, high stumps, snags and logs. The fires decreased the total volume of pre-fire dead wood (23-41%) and consumed logs in late decay stages (26-54%) to a higher extent than logs in earlier stages. The input of new fresh dead wood after the fires exceeded losses of pre-fire dead wood and resulted in a net increase of dead wood in all three sites. The added dead wood consisted of fresh snags killed by the fires. Fire also affected log characteristics: reducing their vegetation coverage (60-98%), decreasing their ground contact (4-50%) and increasing their surface area of charred wood (>50%). Such changes have important consequences for the micro environmental conditions inside logs, but have been rarely studied in relation to restoration fires. Our results show that restoration fire causes changes in dead wood availability and characteristics of logs. The results imply that ideally stands with low abundance of rare and heavily decayed wood substrates should be burned to optimize dead wood values. Alternatively, management practices should include protection of these substrates during restoration fires.

Eriksson, Department of Natural Sciences, Mid Sweden University, SE-851 70, Sundsvall, Sweden E-mail: anna-maria.eriksson@miun.se
Olsson, Department of Ecology and Environmental Science, Umeå University, SE-901 87, Umeå, Sweden E-mail: jorgen.m.olsson@slu.se
Jonsson, Department of Natural Sciences, Mid Sweden University, SE-851 70, Sundsvall, Sweden E-mail: bengt-gunnar.jonsson@miun.se
Toivanen, Department of Natural Sciences, Mid Sweden University, SE-851 70, Sundsvall, Sweden E-mail: sara.toivanen@lansstyrelsen.se
Edman, Department of Natural Sciences, Mid Sweden University, SE-851 70, Sundsvall, Sweden E-mail: mattias.edman@miun.se

article id 952, category Research article

Lauri Korhonen, Inka Pippuri, Petteri Packalén, Ville Heikkinen, Matti Maltamo, Juho Heikkilä. (2013). Detection of the need for seedling stand tending using high-resolution remote sensing data. Silva Fennica vol. 47 no. 2 article id 952. https://doi.org/10.14214/sf.952

Keywords: forest management; airborne laser scanning; logistic regression; seedling stand; tending; support vector machine

Abstract | Full text in HTML | Full text in PDF | Author Info

Seedling stands are problematic in airborne laser scanning (ALS) based stand level forest management inventories, as the stem density and species proportions are difficult to estimate accurately using only remotely sensed data. Thus the seedling stands must still be checked in the field, which results in an increase in costs. In this study we tested an approach where ALS data and aerial images are used to directly classify the seedling stands into two categories: those that involve tending within the next five years and those which involve no tending. Standard ALS-based height and density features, together with texture and spectral features calculated from aerial images, were used as inputs to two classifiers: logistic regression and the support vector machine (SVM). The classifiers were trained using 208 seedling plots whose tending need was estimated by a local forestry expert. The classification was validated on 68 separate seedling stands. In the training data, the logistic model’s kappa coefficient was 0.55 and overall accuracy (OA) 77%. The SVM did slightly better with a kappa = 0.71 and an OA = 86%. In the stand level validation data, the performance decreased for both the logistic model (kappa = 0.38, OA = 71%) and the SVM (kappa = 0.37, OA = 72%). Thus our approach cannot totally replace the field checks. However, in considering the stands where the logistic model predictions had high reliability, the number of misclassifications reduced drastically. The SVM however, was not as good at recognizing reliable cases.

Korhonen, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: lauri.korhonen@uef.fi
Pippuri, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: inka.pippuri@uef.fi
Packalén, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: petteri.packalen@uef.fi
Heikkinen, School of Computing, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: ville.heikkinen@uef.fi
Maltamo, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: matti.maltamo@uef.fi
Heikkilä, Finnish Forest Centre, Public Services, Maistraatinportti 4 A, FI-00240 Helsinki, Finland E-mail: juho.heikkila@metsakeskus.fi

article id 935, category Research article

Loice M. A. Omoro, Mike Starr, Petri K. E. Pellikka. (2013). Tree biomass and soil carbon stocks in indigenous forests in comparison to plantations of exotic species in the Taita Hills of Kenya. Silva Fennica vol. 47 no. 2 article id 935. https://doi.org/10.14214/sf.935

Keywords: biomass; carbon stocks; soil carbon; Eastern Arc Montane forest; exotic tree species; indigenous forest

Abstract | Full text in HTML | Full text in PDF | Author Info

Carbon (C) densities of the tree biomass and soil (0–50 cm) in indigenous forest and plantations of eucalyptus, cypress and pine in the Taita Hills, Kenya were determined and compared. The cypress and pine plantations were about 30-years-old and eucalyptus plantations about 50-years-old. Biomass C densities were estimated from breast height diameter and wood density using allometric functions developed for tropical species and an assumed C content of 50%. Belowground biomass C densities were estimated using root:shoot biomass ratios. Soil organic C (SOC) densities were calculated from measured organic carbon contents (0–20 and 20–50 cm layers) and modelled bulk density values. Mean total biomass C and SOC densities for indigenous forest were greater than those of the plantations, and the difference was significant (p < 0.05) in the cases of cypress and pine biomass and pine SOC. The correlation between biomass C and SOC densities was nearly significant in the case of indigenous forest, but negative. Biomass C densities were not significantly correlated with mean annual precipitation, mean annual temperature or potential evapotranspiration, but pine biomass C densities were significantly correlated to actual evapotranspiration. SOC densities were more strongly correlated to mean annual precipitation than biomass C densities, but only significantly so in the case of pine. Neither biomass C nor SOC densities were correlated to plant available water capacity of the soil. Indigenous forest SOC densities were significantly correlated to soil clay contents, but negatively. Indigenous forests sequester more C in biomass and soil than do 30 to 50-year-old plantations of exotics, but it remains unclear if this is an intrinsic difference between indigenous forest and plantations of exotics or because of insufficient time for SOC levels in plantations to recover after clearance of original indigenous forest.

Omoro, Viikki Tropical Resources Institute, Department of Forest Sciences, P.O. Box 27 (Latokartanonkaari 7), FI-00014 University of Helsinki, Finland E-mail: loice.omoro@helsinki.fi
Starr, Department of Forest Sciences, P. O. Box 27 (Latokartanonkaari 7), FI-00014 University of Helsinki, Finland E-mail: mike.starr@helsinki.fi
Pellikka, Department of Geosciences and Geography, P. O. Box 64 (Gustaf Hällströminkatu 2), FI-00014 University of Helsinki, Finland E-mail: petri.pellikka@helsinki.fi

article id 933, category Research article

Per-Ola Hedwall, Harald Grip, Sune Linder, Lars Lövdahl, Urban Nilsson, Johan Bergh. (2013). Effects of clear-cutting and slash removal on soil water chemistry and forest-floor vegetation in a nutrient optimised Norway spruce stand. Silva Fennica vol. 47 no. 2 article id 933. https://doi.org/10.14214/sf.933

Keywords: Picea abies; logging residues; forest fertilisation; forest undergrowth; N-retention; nutrient leakage; whole-tree harvest

Abstract | Full text in HTML | Full text in PDF | Author Info

Fertilisation with nutrient optimisation has in Sweden resulted in large increases in volume growth in young stands of Norway spruce. There are, however, environmental concerns about repeated fertilisation and one is the risk of nutrient leakage to ground water resources and aquatic ecosystems after clear-cutting of such forests. The present study followed soil-water chemistry in optimised fertilised stands after clear-cutting, as well as effects of harvest of slash on nutrient leakage. Parts of a 30-year-old stand of Norway spruce, which had been subject to a nutrient optimisation experiment for 17 years, were clear-cut. A split-plot design with whole-tree harvesting as the sub-plot treatment was applied. Lysimeters were installed and soil-water sampled at nine occasions during the following four years. No significant effects of fertilisation on nitrate leaching were found, while harvest of slash reduced the concentration of Ca, DOC, DON, K, Mg, ammonium and nitrate, as well as pH in the soil solution. While no effects of fertilisation could be seen on the soil water concentration of N, the results indicate an interaction between fertilisation and harvest of slash on the concentration of nitrate in the soil solution. The results indicate that forest-floor vegetation plays an important role in the retention of N after clear-cutting of fertilised forests.

Hedwall, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences (SLU), P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: per-ola.hedwall@slu.se
Grip, Department of Forest Ecology and Management, SLU, SE-901 83 Umeå, Sweden E-mail: harald@grip2.se
Linder, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences (SLU), P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: sune.linder@slu.se
Lövdahl, Department of Forest Ecology and Management, SLU, SE-901 83 Umeå, Sweden E-mail: ll@nn.se
Nilsson, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences (SLU), P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: urban.nilsson@slu.se
Bergh, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences (SLU), P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: johan.bergh@slu.se

article id 932, category Research article

Jun Wang, Le Shi, Shaoyu Song, Ju Tian, Xiangyang Kang. (2013). Tetraploid production through zygotic chromosome doubling in Populus. Silva Fennica vol. 47 no. 2 article id 932. https://doi.org/10.14214/sf.932

Keywords: Populus; colchicine; high temperature; seed hair; tetraploid induction; zygote

Abstract | Full text in HTML | Full text in PDF | Author Info

The most direct approach in breeding triploid Populus is crossing allotetraploids with diploids. However, the lack of allotetraploid Populus restricts application of this approach. In this investigation, zygotic chromosome doubling was induced with colchicine and high temperatures to produce ((Populus pseudo-simonii × P. nigra ‘Zheyin3#’) × (P. × beijingensis)) allotetraploids. We screened 6 and 25 tetraploid individual offspring from the colchicine and high-temperature treatments respectively, indicating that both colchicine and high temperature are effective for tetraploid production by zygotic chromosome doubling of Populus. Developmental characteristics of seed hairs in the ovaries were temporally associated with zygotic development, which was used to successfully guide the colchicine and high-temperature treatments. During certain stages of hair development, the efficiency of tetraploid production was significantly high. However, efficiency of production was not significantly influenced by other factors, i.e. colchicine concentration, temperature or duration of high-temperature treatment. Size and frequency of leaf stomata between tetraploid and diploid plants were significantly different, suggesting that this character can be altered via genomic increase in material. The allotetraploids produced in this investigation, having different genotypes, provide important parental germplasms for further triploid breeding.

Wang, National Engineering Laboratory for Tree Breeding; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education; College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P.R. China E-mail: wangjun@bjfu.edu.cn
Shi, National Engineering Laboratory for Tree Breeding; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education; College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P.R. China E-mail: 7320932@qq.com
Song, National Engineering Laboratory for Tree Breeding; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education; College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P.R. China E-mail: angela-song@foxmail.com
Tian, National Engineering Laboratory for Tree Breeding; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education; College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P.R. China E-mail: 1215813245@qq.com
Kang, National Engineering Laboratory for Tree Breeding; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education; College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P.R. China E-mail: kangxy@bjfu.edu.cn

article id 930, category Research article

Raffaele Spinelli, Eugenio Cavallo, Lars Eliasson, Alessio Facello. (2013). Comparing the efficiency of drum and disc chippers. Silva Fennica vol. 47 no. 2 article id 930. https://doi.org/10.14214/sf.930

Keywords: productivity; biomass; wood; energy; fuel

Abstract | Full text in HTML | Full text in PDF | Author Info

The study compared the effect of chipper type on productivity, power demand, fuel consumption and product quality. Tests were conducted on two commercial chipper models, a disc and a drum chipper. Both chippers had the same diameter capacity, were applied to the same tractor and fed with the same feedstock types. Fifteen replications were conducted per machine and for each of four different feedstock types, reaching a total of 120 tests. The disc chipper had a higher energy efficiency and used 19% less fuel per unit product, possibly due to its simpler design, integrating comminuting and discharge system in one synergic device. In contrast, the drum chipper was 8% more productive, since it cut with the same energy all along the length of its knives. The drum chipper produced smaller chips, with a higher incidence of fines. Feedstock type had a strong effect on productivity, energy efficiency and product quality. The effect of feedstock type was mainly related to piece size, and may be stronger than the effect of chipper type. Further studies should determine the effect of blade wear on the relative performance of the two chipper types.

Spinelli, CNR IVALSA, Via Madonna del Piano 10, Sesto Fiorentino (FI), Italy E-mail: spinelli@ivalsa.cnr.it
Cavallo, CNR IVALSA, Via Madonna del Piano 10, Sesto Fiorentino (FI), Italy E-mail: e.cavallo@imamoter.cnr.it
Eliasson, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: lars.eliasson@skogforsk.se
Facello, CNR IVALSA, Via Madonna del Piano 10, Sesto Fiorentino (FI), Italy E-mail: a.facello@ima.to.cnr.it

article id 928, category Research article

Rune Simonsen. (2013). Optimal regeneration method – Planting vs. natural regeneration of Scots pine in northern Sweden. Silva Fennica vol. 47 no. 2 article id 928. https://doi.org/10.14214/sf.928

Keywords: optimisation; silviculture; genetically improved planting material

Highlights: Two regeneration methods were modelled on stand level and optimised numerically to maximise present value for a range of site indexes and locations; Natural regeneration was optimal in most cases; Planting was optimal for high site indexes, low rate of seedling mortality and for low discount rates; Using genetically improved plant material greatly shifts the preference towards planting

Abstract | Full text in HTML | Full text in PDF | Author Info

In this study the profitability of regenerating Scots pine (Pinus sylvestris L.) was examined for two methods; planting and natural regeneration with seed trees. The methods were modelled on stand level and optimised numerically using nonlinear optimisation. The analysis includes 7 site indexes, 16 to 28 expressed as dominant height in meters at an age of 100 years; and 8 localities in northern Sweden distributed on two latitudes, 60°N and 64°N and four altitudes, 100 to 400 m.a.s.l. Furthermore, two scenarios of genetically improved planting material were examined. The results show that the optimal choice of regeneration method depends on the location, site index and discount rate. Considering the same genetic regeneration material, natural regeneration was the optimal method for most of the evaluated sites. Planting was optimal only for stands of high site index and low rate of seedling mortality, which is associated with localities on low altitudes. The break even site index, where the two methods yielded the same net present value, was 27 on average (25 to 28). The choice between the two regeneration methods was found to be more economically important when the discount rate was low and for low site indexes. The option of using genetically improved plant material shift the preference towards planting. Thus, the two levels of genetic gain of +4% and +10% to maximum mean annual increment resulted in an average break even site index of 25 and 21 respectively.

Simonsen, Department of Forest Economics, SLU, SE-901 83 Umeå, Sweden E-mail: rune.simonsen@slu.se

Category : Research note

article id 960, category Research note

Shou-Qin Sun, Liang Peng, Gen-Xu Wang, Yan-Hong Wu, Jun Zhou, Hai-Jian Bing, Dong Yu, Ji Luo. (2013). An improved open-top chamber warming system for global change research. Silva Fennica vol. 47 no. 2 article id 960. https://doi.org/10.14214/sf.960

Keywords: climate change; temperature; open-top chamber; OTC-cable system; forest ecosystem

Abstract | Full text in HTML | Full text in PDF | Author Info

This study is an assessment of an improved temperature warming system developed to enhance global warming research-based forest ecosystem and soil ecophysiological experiments. The architecture couples a standard open-top chamber (OTC) with a heating cable. A 16 m wire cable with an 18 W m^-1 and 288 W h^-1 power rating was coiled around a polyvinyl chloride (PVC) pipe 2.5 m in length and 3.5 cm in diameter. The pipe was reshaped into a circle and fixed inside the OTC at a height of 15 cm. PVC pipe distance to plants was 10 to 15 cm while distance to OTC inner walls was 15 cm. The cable was constructed from a heating source with an alloy resistance wire, an aluminum foil and copper wire shielded layer, a crosslinking polyethylene inner insulator, a PVC coating, and a tinned copper grounding wire. After the cable is powered up, air and soil inside the OTC-cable system is heated by conductivity. Temperature is manipulated according to the voltage and resistance of the cable. The OTC-cable system was developed to examine plant reaction to an increase in air and soil temperatures by 2.84 °C and 1.83 °C, respectively. Temperature values are adjustable by changing cable and PVC pipe length. It offers a new, affordable, low energy consumption and low running cost method by which to study climate change effects on forest ecosystems. This method is especially useful for application in forest ecosystems of many developing countries or in many remote areas of developed countries where the feasibility in supplying sufficient power from local power grids is questionable.

Sun, Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, No. 9, Block 4, South Renmin Road, Chengdu, China, 610041 E-mail: shouqinsun@imde.ac.cn
Peng, Horticulture and Landscape College, Hunan Agricultural University, Furong District, Changsha, China, 410128 E-mail: keith215@126.com
Wang, Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China E-mail: cookiedot@sina.cn
Wu, Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China E-mail: free2001@tom.com
Zhou, Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China E-mail: haitaosun@sohu.com
Bing, Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China E-mail: 78186181@qq.com
Yu, Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China E-mail: dongdyu@sohu.com
Luo, Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China E-mail: 1254157095@qq.com

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