Articles containing the keyword 'monitoring'

A calculation procedure is presented for calculating and analysing remeasured permanent sample plots. Data for eight different fixed and variable size plot types were simulated on the basis of two stands whose trees were mapped and measured in 1982 and 1986. The accuracy and efficiency of the plot types were assessed and compared.

The calculation procedure is based on tree-wise expansion factors and the division of tree sampled into state/measurement classes. Nine classes were required for variable size plots and six for fixed size plots. A relascope plot with basal-area factor 1 (m²/ha) proved to be most efficient for estimating basal-area at a given time and a fixed size circular plot with radius 10 m for estimating basal-area increment over a given time period.

The main problems were related to the estimation of non-measurable variables, e.g., the initial diameters of ingrowth trees, i.e., trees having passed the threshold size during the measurement period. Most problematic were cut trees belonging to the ingrowth or sample enlargement classes. It is nevertheless thought that the system is appropriate for monitoring forest changes and making sensitivity analyses with permanent sample plots.

• Poso, E-mail: sp@mm.unknown
• Waite, E-mail: mw@mm.unknown

A range of different indices are available for assessing the health of trees in forests. An even larger range can be used for the assessment of the health of forest ecosystems. Most studies made in connection with ”forest decline” and the impact of air pollution and other environmental stresses on forests have concentrated on the assessment of crown transparency and crown discoloration in individual trees. These are non-specific indicators which are now known to be sometimes of relatively little value when determining the health of a forest ecosystem. Numerous problems exist with both, and the standardisation of assessments between and even within countries has not been achieved. Consequently, studies claiming to compare ”defoliation” between different countries cannot be substantiated. The emphasis on crown transparency and crown discoloration has resulted in the neglect of a number of other indices that could be of considerable value. These include a variety of visual measures of crown condition and also several non-visual bioindicators. Some of these techniques are objective, reducing the present reliance on observed standardization. A large number of potential techniques are currently at the research stage and have yet to be adequately tested in field trials. This represent an area where a substantial amount of further research is required.

• Innes, E-mail: ji@mm.unknown

A third generation of forest tree gas exchange measuring system design for the use in the field is described. The system is designed to produce data for determining the dependence of the rate of tree photosynthesis, respiration and transpiration on environmental factors. The system consists of eight cuvettes, a tubing system, two infrared gas analysers, an air flow controller, a data logger, and a computer. The measuring cuvette is a clap type, i.e. it is mostly open, only closing during measurement. CO₂ exchange is measured as the change in the cuvette concentration of CO₂, and, transpiration is measured as the increase in water vapour concentration while the cuvette is closed. The environmental factors measured are temperature, irradiance and air pressure. The system was planned in 1987 and constructed in 1988. It worked reliably in late summer 1988 and the quality of data seems to be satisfactory. 

The PDF includes an abstract in Finnish.

• Hari, E-mail: ph@mm.unknown
• Korpilahti, E-mail: eeva.korpilahti@luke.fi
• Pohja, E-mail: tp@mm.unknown
• Räsänen, E-mail: pr@mm.unknown

The woodland mosses Pleurozia shcreberi (Willd. ex Brid.) Mitt. and Hylocomnium splendens (Hedw.) Schimp. were used in air pollution monitoring. During late summer and autumn 1977, 44 samples of Pleurozia shcreberi were collected in semi-open coniferous forests from Southern Finland (60°N) to Northern Finland and Northern Norway (70°N). Additional 26 samples of Hylocomnium splendens were collected in similar places south of 61°30’N. Analysis of both moss species revealed decreasing concentration gradients from south to north for Cu, Fe, Pb and Zn. Conversely, Mn and Mg levels increased with latitude, while Ca did not change significantly. Some decreasing west to east concentration gradients for Cu, Zn and Pb were measured in P. schreberi and in H. splendends collected from Southern Finland.

A comparison between these two mosses showed significant differences in Cu content (ave. 22% higher in H. splendends) and Zn content (ave. 8% higher in P. schreberi). However, the differences were considered minor in relation to regional differences in Finland.

In local study of emissions from the Koverhar steel works in Southern Finland, Fe and Zn concentrations in P. schreberi and H. splendens were found to decrease significantly with increasing distance up to 6 kilometres north and south of the source.

The PDF includes a summary in Finnish.

• Rinne, E-mail: rr@mm.unknown
• Mäkinen, E-mail: am@mm.unknown

A method for using satellite data in forest inventories and updating is described and tested. The stand characteristics estimated by the method showed high correlation with the same characteristics measured in the field. The correlation coefficients for volume, age and mean height were about 0.85. It seems that the method is applicable to practical forestry. Extensive work in programming, however, is required.

The PDF includes an abstract in Finnish.

• Poso, E-mail: sp@mm.unknown
• Paananen, E-mail: rp@mm.unknown
• Similä, E-mail: ms@mm.unknown

A semi-statistical model is suggested for monitoring injuries of plants for long-time field exposures (months). The model is based on the following assumptions:

1. The concentrations of air pollutants in the atmosphere follow the Johnson SB distribution.

2. The degree of plant injury is proportional to the logarithm of air pollutant dose.

3. No injuries occur below a certain dose level.

4. A dose is defined as the air pollutant concentration multiplied by the duration of exposure raised to an exponent.

Based on the air pollutant frequency distribution a total dose for the exposure period is calculated by integration, and the total dose is related to the observed plant injury by non-linear regression. The model is tested for long-time exposures of sulphur dioxide to transplant lichen in natural environment.

• Moseholm, E-mail: lm@mm.unknown

A monitoring program is planned for the terrestrial environment around industries in Sweden, which emit acid compounds and heavy metals. Directions for the County Government Boards are being prepared. The paper deals with the present pollution situation in Sweden, based on recent scientific results, the justifications for local monitoring, and the organizing of the monitoring including the parameters suggested.

Four examples from a case study at an oil power station illustrate reporting of the data and the difficulties in interpreting the results. The examples are the distribution of a lichen indicator, heavy metal content and phosphatase activity in the moor layer, soil respiration and tree growth.

• Westman, E-mail: lw@mm.unknown

• Peltoniemi, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: mikko.peltoniemi@metla.fi
• Heikkinen, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: jh@nn.fi
• Mäkipää, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: raisa.makipaa@metla.fi

In 2019–2023 the 13th Finnish National Forest Inventory (NFI) was implemented by measuring a total of 62 266 sample plots across the country. The methodology of the sampling and measurements was similar as in the previous inventory, but the proportion and number of remeasured permanent plots was increased to improve the monitoring of annual increment and other changes in the forests. Only 6.2 M ha (14%) of Finland’s total land area (30.4 M ha) is other land than forestry land. Productive and poorly productive forests cover 22.9 M ha (75%) of the total land area.  The forest area has remained stable in recent decades but the forest area available for wood supply (FAWS) has decreased due to increased forest protection – 23% of the forestry land and 10% of the productive forest are not available for wood supply. Compared to the previous inventory, forest resources have continued to increase but the average annual increment has declined from 107.8 M m³ to 103.0 M m³. The quality of forests from the timber production point of view has remained relatively good or improved slightly. The area of observed forest damage on FAWS is 8.4 M ha (46% of FAWS area), half of these minor damages with no impact on stand quality. Although the area of forest damage has not increased, the amount of mortality has continued to increase, and is now 8.8 M m³ year^–1. The amount of dead wood has continued to increase in South Finland, while in North Finland the declining trend has turned into a slight increase. Since the 1920s, the area of forestry land has remained stable, but the area of productive forest has increased due to the drainage of poorly productive or treeless peatlands. The total volume of growing stock has increased by 84% and annual increment has more than doubled.

• Korhonen, Natural Resources Institute Finland (Luke), P.O.Box 68, FI-80100 Joensuu, Finland https://orcid.org/0000-0002-6198-853X E-mail: kari.t.korhonen@luke.fi
• Räty, Natural Resources Institute Finland (Luke), P.O.Box 2, FI-00790, Helsinki, Finland https://orcid.org/0000-0001-9898-8712 E-mail: minna.raty@luke.fi
• Haakana, Natural Resources Institute Finland (Luke), P.O.Box 2, FI-00790, Helsinki, Finland E-mail: helena.haakana@luke.fi
• Heikkinen, Natural Resources Institute Finland (Luke), P.O.Box 2, FI-00790, Helsinki, Finland https://orcid.org/0000-0003-3527-774X E-mail: juha.heikkinen@luke.fi
• Hotanen, Natural Resources Institute Finland (Luke), P.O.Box 68, FI-80100 Joensuu, Finland E-mail: juha-pekka.hotanen@luke.fi
• Kuronen, Natural Resources Institute Finland (Luke), P.O.Box 2, FI-00790, Helsinki, Finland https://orcid.org/0000-0002-8089-7895 E-mail: mikko.kuronen@luke.fi
• Pitkänen, Natural Resources Institute Finland (Luke), P.O.Box 68, FI-80100 Joensuu, Finland https://orcid.org/0000-0002-7583-6297 E-mail: juho.pitkanen@luke.fi

In the forest areas of eastern China, there is a change from forest dominated by deciduous broad-leaved trees to forest dominated by evergreen broad-leaved trees as the latitude or altitude decreases. Different life forms have different survival strategies to deal with climate change, and studying the life form dynamics of the tree layers in the mixed forest in eastern China, with increasing temperature, can help us understand how the forest responds. This study was performed in a 1 ha plot in evergreen and deciduous broad-leaved mixed forest in Tianmu Mountain National Nature Reserve. Based on the data from two surveys (1996 and 2017), the changes in life form composition and biodiversity over the past 21 years were analyzed. We obtained the following results: (1) The proportion of evergreen trees increased from 55.0% in 1996 to 67.5% in 2017, and the dominance of evergreen species was enhanced. (2) The diversity of both life forms increased, and the tree species were more abundant. (3) The average annual recruitment rate of the evergreen species was 2.1% greater than their mortality rate, and the average annual recruitment rate of the deciduous species was 0.5% less than their mortality rate. (4) The competition among the trees in the small-diameter class (10 cm ≤ DBH < 20 cm) was fierce for many tree species. The proportion of the evergreen species in the small-diameter class was high. The life forms making up the mixed climax forest community has changed over the past 21 years, with the proportion and dominance of evergreen trees increasing significantly.

• Bai, State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China E-mail: baicheng111@gmail.com
• You, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310011, China E-mail: sxyou@zju.edu.cn
• Ku, State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China E-mail: 2732684475@qq.com
• Dai, State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China E-mail: 757692949@qq.com
• Wang, State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China E-mail: 237600341@qq.com
• Zhao, Management Bureau of Tianmu Mountain National Nature Reserve, Hangzhou 311311, China E-mail: 973659738@qq.com
• Yu, State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China E-mail: yushq@zafu.edu.cn

• Wulff, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden E-mail: soren.wulff@slu.se
• Roberge, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden E-mail: cornelia.roberge@slu.se
• Ringvall, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden E-mail: anna.ringvall@slu.se
• Holm, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden E-mail: soren.holm@slu.se
• Ståhl, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden E-mail: goran.stahl@slu.se

• Holzleitner, Institute of Forest Engineering, Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences, Peter Jordanstrasse 82/3, 1190 Vienna, Austria E-mail: franz.holzleitner@boku.ac.at
• Kanzian, Institute of Forest Engineering, Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences, Peter Jordanstrasse 82/3, 1190 Vienna, Austria E-mail: christian.kanzian@boku.ac.at
• Höller, Institute of Forest Engineering, Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences, Peter Jordanstrasse 82/3, 1190 Vienna, Austria E-mail: norbert.hoeller@boku.ac.at

• Eskelson, Oregon State University, Department of Forest Engineering, Resources and Management, 204 Peavy Hall, Corvallis, Oregon 97331, USA E-mail: bianca.eskelson@oregonstate.edu
• Barrett, Oregon State University, Department of Forest Engineering, Resources and Management, 204 Peavy Hall, Corvallis, Oregon 97331, USA E-mail: tmb@nn.us
• Temesgen, Oregon State University, Department of Forest Engineering, Resources and Management, 204 Peavy Hall, Corvallis, Oregon 97331, USA E-mail: ht@nn.us

• Korpela, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: ilkka.korpela@helsinki.fi

• Malmivaara, Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland E-mail: minna.malmivaara@metla.fi
• Löfström, Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland E-mail: il@nn.fi
• Vanha-Majamaa, Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland E-mail: ivm@nn.fi

• Edenius, SLU, Department of Animal Ecology, SE-901 83 Umeå, Sweden E-mail: lars.edenius@szooek.slu.se
• Bergman, SLU, Department of Animal Ecology, SE-901 83 Umeå, Sweden E-mail: mb@nn.se
• Ericsson, SLU, Department of Animal Ecology, SE-901 83 Umeå, Sweden E-mail: ge@nn.se
• Danell, SLU, Department of Animal Ecology, SE-901 83 Umeå, Sweden E-mail: kd@nn.se

• Kuuluvainen, Department of Forest Ecology, University of Helsinki, P.O.Box 27 FIN-00014, Finland E-mail: timo.kuuluvainen@helsinki.fi
• Aapala, Finnish Environment Institute, Expert Services Department, Nature Division, P.O. Box 140, FIN-00251 Helsinki E-mail: ka@nn.fi
• Ahlroth, University Museum, Section of Natural History, P.O. Box 35, FIN-40351, Jyväskylä, Finland E-mail: pa@nn.fi
• Kuusinen, Ministry of the Environment, Land Use Department, P.O.Box 380, FIN-00131 Helsinki, Finland E-mail: mk@nn.fi
• Lindholm, Finnish Environment Institute, Expert Services Department, Nature Division, P.O. Box 140, FIN-00251 Helsinki E-mail: tl@nn.fi
• Sallantaus, Pirkanmaa Regional Environment Centre, P.O. Box 297, FIN-33101 Tampere, Finland E-mail: ts@nn.fi
• Siitonen, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland E-mail: juha.siitonen@metla.fi
• Tukia, Finnish Environment Institute, Expert Services Department, Nature Division, P.O. Box 140, FIN-00251 Helsinki E-mail: ht@nn.fi