Articles containing the keyword 'leaf'
Category : Article
The purpose of this article was to collate the literature on fungal diseases that occur on seedlings in forest nurseries. It describes the symptoms of the diseases, the infection pattern of each fungus and the possibilities of controlling the diseases. As background a short introduction is given on forests and nursery practices in Finland.
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Lilja,
E-mail:
al@mm.unknown
- Kurkela, E-mail: tk@mm.unknown
- Lilja, E-mail: sl@mm.unknown
- Rikala., E-mail: rr@mm.unknown
The aim of the study was to compare the behaviour of three selected provenances of Eucalyptus microtheca F. Muell. that were likely to respond differently to drought. For this purpose, we studied the effects of vapour pressure deficit and soil water content on leaf water potential in an irrigated plantation in Bura, eastern Kenya.
An international provenance trial of Eucalyptus microtheca, established as a part of Finnida-supported Bura Forestry Research Project in eastern Kenya in 1984 was used as a plant material in the study. The eastern provenance showed generally the lowest leaf water potential on a daily basis. Statistically significant differences in the daily leaf water potential fluctuations were detected. The eastern provenance exhibited the greatest and the northern one the smallest values. The minimum daily leaf water potential of the provenances responded well to changes in gravimetric soil water content, the western provenance being the most sensitive one. The relationship of the observed results and annual rainfall distribution in the geographic regions of the studied provenances is discussed.
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Tuomela,
E-mail:
kt@mm.unknown
- Kanninen, E-mail: mk@mm.unknown
Variation in needle nutrient concentrations with age and vertical location in the crown was studied in three Scots pine (Pinus sylvestris L.) stands growing on peat soils in Eastern Finland. The concentrations of N, P, Fe and Zn decreased down the crown and those of Ca and Mn increased. Potassium and magnesium concentration patterns differed between sites.
Potassium and Mg concentrations were highest in the current needles at all heights in the crown, iron and manganese concentrations were highest in the oldest needles. The concentrations of N, P and Zn did not vary with needle age.
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Finér,
E-mail:
lf@mm.unknown
A technique for instrumental scoring of damaged leaves on tobacco (Nicotiana tabacum) indicator plants caused by ozone in the lower atmosphere is being developed. The leaves are photographed in situ with an integrated unit, which illuminates the leaf from behind and keeps the camera in a well-defined position. By using microfilm and a minus green filter, it is possible to obtain negatives where the necrotic flecks appear as dark spots on a white leaf. The negatives are scanned in a TV-system and the size of the damaged fraction of the leaf is calculated by a microprosessor and is shown as a percentage of the leaf.
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Mortensen,
E-mail:
lm@mm.unknown
- Weisberg, E-mail: kw@mm.unknown
A forest damage was detected in spring 1931 near electro-chemical factory in Imatra in Eastern Finland. It was deduced that it was caused by a gas discharge from the factory. A survey was made to describe the damages. Forests in the damaged area of five hectares were Scots pine (Pinus sylvestris L.) dominated and 60-80 years old. According to the factory, the exhaust gases contained 0.4 mg chlorine per liter. In addition, chlorate containing liquids evaporated thorough the chimney, which seemed to have been the main cause of the damage. The chlorates may have concentrated in the snow covering the trees during the winter. The Scots pine trees had lost all the needles in spring, but grew new needles in the summer. In some trees the new needles were few or undeveloped. Some mild damages were noticed in pine and Betula sp. during the growing season. Forest edges and trees higher that the other trees were worst damaged. Pine was most sensitive to the emission. Pine weakened by the gas damages were attacked by insects, the most important being Pissodes sp. The secondary insect damage is likely to kill the surviving trees. The dying pines should be removed only if it is necessary to prevent the spreading of insect damage. The trees may hinder the spreading of further gas emissions. In future, other tree species should be preferred over pine.
The PDF includes a summary in German.
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Kangas,
E-mail:
ek@mm.unknown
Category : Article
In South-West Finland the usual method to make leaf fodder for cattle has been to cut the branches and collect the new sprouts again next year. According to this review, the most common tree species to be topped is Betula sp. Downy Birch (Betula pubescens Ehrh.) grows shoots easier than silver birch (B. pendula Roth). The topped forests are usually small and situated near the settlements, next to the fields and meadows. The birch trees are typically cut when they are 15-20 years old. Regularly topped birch rots easily and seldom exceeds 50 years. The capacity to grow shoots depends on the age of the tree, site and time of the cutting. The risk for rotting can be decreased by removing only part of the shoots and cutting the shoots a short distance from the base of the shoot. Collecting leaf fodder decreased in Finland, and was common only in the South-West Finland and Åland.
The PDF includes a summary in German.
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Lukkala,
E-mail:
ol@mm.unknown
The aim of this study was to investigate the ecophysiological and morphological characteristics of two salt-tolerant tree species, Eucalyptus camaldulensis Dehn. and Combretum quadrangulare Kurz. A greenhouse experiment with different levels of NaCl salinity (0, 0.5, 1.0, 1.5, and 2.0%) was set up and the results were compared with those of a field study on non-saline and saline soils. The determination of optimum gas exchange and the development and evaluation of photosynthetic models with and without water deficit were also included in this study.
Morphological characteristics under saline conditions showed that shoot height and diameter growth, shoot internode length, root length/biomass, leaf width and length, leaf area, number and biomass, and shoot/root and leaf/root ratios decreased with salinity, while leaf thickness increased with salinity. More growth was allocated to the roots than to the leaf canopy. Ecophysiological studies in laboratory showed that photosynthesis, stomatal conductance and water potential decreased with salinity, while the CO2 compensation point increased with salinity. Transpiration, dark respiration and photorespiration increased at low salinity but decreased at high salinity levels. In the field study, however, there were no significant differences in stomatal conductance and opening between saline and non-saline soils. Model predictions supported the results of the field measurements. Adaptation to salinity was reflected in an acclimatization of tree structure in the field study. There were both functioning and structural changes of seedlings in the greenhouse experiment
In terms of ecophysiological and morphological characteristics, E. Camaldulensis showed better salt tolerance than C. Quadragulare both in the greenhouse experiment and field study
The PDF includes a summary in Finnish.
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Luangjame,
E-mail:
jl@mm.unknown
Genetic variation in the physiological characteristics and biomass accumulation of Acacia mangium Willd. was studied in both field and laboratory conditions. Variation in the growth characteristics, foliar nutrient concentration, phyllode anatomy and stomatal frequency was analysed in 16 different origins under field conditions in Central Thailand. Family variation and heritability of growth and flowering frequency were calculated using 20 open-pollinated families at the age of 28 months. The effect of environmental factors on diameter growth in different provenances is also discussed.
Under laboratory conditions, such physiological characteristics as transpiration rate, leaf conductance and leaf water potential were measured at varying soil moisture conditions. The responses of photosynthesis, photorespiration and dark respiration as well as the CO2 compensation point to temperature and irradiance were also investigated. All physiological characteristics indicated differences among provenances. An attempt was made to relate the results obtained in the laboratory to the growth performance in the field. Recommendations on provenance selection for the planting of A. mangium in Thailand are also given.
The PDF includes a summary in Finnish.
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Atipanumpai,
E-mail:
la@mm.unknown
Category : Research article
Accurate assessment of canopy structure is crucial in studying plant-environment interactions. The advancement of functional-structural plant models (FSPM), which incorporate the 3D structure of individual plants, increases the need for a method for accurate mathematical descriptions of leaf shape. A model was developed as an improvement of an existing leaf shape algorithm to describe a large variety of leaf shapes. Modelling accuracy was evaluated using a spatial segmentation method and shape differences were assessed using principal component analysis (PCA) on the optimised parameters. Furthermore, a method is presented to calculate the mean shape of a dataset, intended for obtaining a representative shape for modelling purposes. The presented model is able to accurately capture a large range of single, entire leaf shapes. PCA illustrated the interpretability of the parameter values and allowed evaluation of shape differences. The model parameters allow straightforward digital reconstruction of leaf shapes for modelling purposes such as FSPMs.
- Coussement, Plant Sciences Unit, Institute for Agricultural and Fisheries Research (ILVO), Caritasstraat 39, B-9090 Melle, Belgium; Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B-9000 Ghent, Belgium E-mail: jonas.coussement@ilvo.vlaanderen.be
- Steppe, Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B-9000 Ghent, Belgium E-mail: kathy.steppe@ugent.be
- Lootens, Plant Sciences Unit, Institute for Agricultural and Fisheries Research (ILVO), Caritasstraat 39, B-9090 Melle, Belgium E-mail: peter.lootens@ilvo.vlaanderen.be
- Roldán-Ruiz, Plant Sciences Unit, Institute for Agricultural and Fisheries Research (ILVO), Caritasstraat 39, B-9090 Melle, Belgium; Department of Plant Biotechnology and Bioinformatics, Faculty of Sciences, Ghent University, Technologiepark Zwijnaarde 927, B-9052 Zwijnaarde, Belgium E-mail: isabel.roldan-ruiz@ilvo.vlaanderen.be
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De Swaef,
Plant Sciences Unit, Institute for Agricultural and Fisheries Research (ILVO), Caritasstraat 39, B-9090 Melle, Belgium
E-mail:
tom.deswaef@ilvo.vlaanderen.be
Spectral libraries have a fundamental role in the development of interpretation methods for airborne and satellite-borne remote sensing data. This paper presents to-date the largest spectral measurement campaign of boreal tree species. Reflectance and transmittance spectra of over 600 leaf and needle samples from 25 species were measured in the Helsinki area (Finland) using integrating sphere systems attached to an ASD FieldSpec 4 spectroradiometer. Factors influencing the spectra and red edge inflection point (REIP) were quantified using one-way analysis of variance. Tree species differed most in the shortwave-infrared (1500–2500 nm) and least in the visible (400–700 nm) wavelength region. Species belonging to same genera showed similar spectral characteristics. Upper (adaxial) and lower (abaxial) leaf sides differed most in the visible region. Canopy position (sunlit/shaded) had a minor role in explaining spectral variation. For evergreen conifers, current and previous year needles differed in their spectra, current-year needles resembling those of broadleaved and deciduous conifers. Two broadleaved species were monitored throughout the growing season (May–October), and two conifers were measured twice during summer (June, September). Rapid changes were observed in the spectra in early spring and late autumn, whereas seasonal variations during summer months were relatively small for both broadleaved and coniferous species. Based on our results, shortwave-infrared seems promising in separating tree species, although it is to-date least studied. The spectral library reported here (Version 1.0) is publicly available through the SPECCHIO Spectral Information System.
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Hovi,
Aalto University, Department of Built Environment, P.O. Box 14100, FI-00076 Aalto, Finland
E-mail:
aarne.hovi@aalto.fi
- Raitio, Aalto University, Department of Built Environment, P.O. Box 14100, FI-00076 Aalto, Finland E-mail: pekka.raitio@aalto.fi
- Rautiainen, Aalto University, Department of Built Environment, P.O. Box 14100, FI-00076 Aalto, Finland; Aalto University, Department of Electronics and Nanoengineering, P.O. Box 15500, FI-00076 Aalto, Finland E-mail: miina.a.rautiainen@aalto.fi
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Henke,
Department Ecoinformatics, Biometrics & Forest Growth, University of Göttingen, 37077 Göttingen, Germany
E-mail:
mhenke@uni-goettingen.de
- Huckemann, Institute of Mathematical Stochastics, University of Göttingen, 37077 Göttingen, Germany E-mail: huckeman@math.uni-goettingen.de
- Kurth, Department Ecoinformatics, Biometrics & Forest Growth, University of Göttingen, 37077 Göttingen, Germany E-mail: wk@informatik.uni-goettingen.de
- Sloboda, Department Ecoinformatics, Biometrics & Forest Growth, University of Göttingen, 37077 Göttingen, Germany E-mail: bslobod@web.de
- Villikka, University of Easten Finland, Department of Forest Sciences, Joensuu, Finland E-mail: mv@nn.fi
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Packalén,
University of Easten Finland, Department of Forest Sciences, Joensuu, Finland
E-mail:
petteri.packalen@uef.fi
- Maltamo, University of Easten Finland, Department of Forest Sciences, Joensuu, Finland E-mail: mm@nn.fi
- Hou, Department of Life Sciences, Shangqiu Normal University, Shangqiu, China E-mail: yh@nn.cn
- Qu, Department of Life Sciences, Shangqiu Normal University, Shangqiu, China E-mail: jq@nn.cn
- Luo, School of Environment and Life Sciences, Kaili University, Kaili, China E-mail: zl@nn.cn
- Zhang, Shanghai Key Laboratory of Urbanization and Ecological Restoration, East China Normal University, Shanghai, China, and University of Eastern Finland, School of Forest Sciences, Joensuu, Finland E-mail: cz@nn.cn
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Wang,
Shanghai Key Laboratory of Urbanization and Ecological Restoration, East China Normal University, Shanghai, China, and University of Eastern Finland, School of Forest Sciences, Joensuu, Finland
E-mail:
kywang@re.ecnu.edu.cn
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Vaario,
Finnish Forest Research Institute, Vantaa Research Unit, P. O. Box 18, FI-01301 Vantaa, Finland
E-mail:
lu-min.vaario@metla.fi
- Yrjälä, MEM group, Department of Biosciences, P.O. Box 56, FI-00014 University of Helsinki, Finland E-mail: ky@nn.fi
- Rousi, Finnish Forest Research Institute, Vantaa Research Unit, P. O. Box 18, FI-01301 Vantaa, Finland E-mail: matti.rousi@metla.fi
- Sipilä, Department of Agricultural Sciences, P.O. Box 56, FI-00014 University of Helsinki, Finland E-mail: ts@nn.fi
- Pulkkinen, Pulkkinen, Finnish Forest Research Institute, Haapastensyrjä Research Unit, Haapastensyrjäntie 34, FI-12600 Läyliäinen, Finland E-mail: pertti.pulkkinen@metla.fi
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Sumida,
Institute of Low Temperature Science, Hokkaido University, N19W8, Sapporo 060-0819, Japan
E-mail:
asumida@lowtem.hokudai.ac.jp
- Nakai, International Arctic Research Center, University of Alaska Fairbanks, 930 Koyukuk Drive, P.O. Box 757340, Fairbanks, Alaska 99775-7340, USA E-mail: tn@nn.jp
- Yamada, International Meteorological & Oceanographic Consultants Co., Ltd. Kawaguchi-cho 2-6528-87, Choshi, Chiba 288-0001, Japan E-mail: my@nn.jp
- Ono, Institute of Low Temperature Science, Hokkaido University, N19W8, Sapporo 060-0819, Japan E-mail: ko@nn.jp
- Uemura, Field Science Center for Northern Biosphere, Hokkaido University, Tokuda 250, Nayoro, Hokkaido 096-0071, Japan E-mail: su@nn.jp
- Hara, Institute of Low Temperature Science, Hokkaido University, N19W8, Sapporo 060-0819, Japan E-mail: th@nn.jp
- Kang, School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240, P. R. China E-mail: hk@nn.cn
- Berg, Department of Forest Ecology, University of Helsinki, Latokartanonkaari 7, FIN-00014 Finland; Dipartimento Biologia Strutturale e Funzionale. Complesso Universitario, Monte S. Angelo, Via Cinthia, IT-80126 Napoli, Italy E-mail: bb@nn.fi
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Liu,
School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240, P. R. China; Key Laboratory of Urban Agriculture (South), Ministry of Agriculture, P. R. China, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, P. R. China
E-mail:
chjliu@sjtu.edu.cn
- Westman, Dipartimento Biologia Strutturale e Funzionale. Complesso Universitario, Monte S. Angelo, Via Cinthia, IT-80126 Napoli, Italy E-mail: cjw@nn.it
- Steinke, Plant Ecology and Systematics, Lund University, Ecology Department, 223 62 Lund, Sweden E-mail: lks@nn.se
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Premoli,
Universidad Nacional del Comahue, Laboratorio Ecotono – CRUB, Quintral 1250, 8400 Bariloche, Argentina
E-mail:
apremoli@crub.uncoma.edu.ar
- Souto, Universidad Nacional del Comahue, Laboratorio Ecotono – CRUB, Quintral 1250, 8400 Bariloche, Argentina E-mail: cps@nn.ar
- Hedrén, Plant Ecology and Systematics, Lund University, Ecology Department, 223 62 Lund, Sweden E-mail: mh@nn.se
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Li,
Chengdu Institute of Biology, Chinese Academy of Sciences, P.O. Box 416, Chengdu 610041, P. R. China
E-mail:
licy@cib.ac.cn
- Zhang, Chengdu Institute of Biology, Chinese Academy of Sciences, P.O. Box 416, Chengdu 610041, P. R. China; Graduate School of the Chinese Academy of Sciences, Beijing 100039, P.R. China E-mail: xz@nn.cn
- Liu, Sichuan Academy of Forestry, Chengdu 610081, P. R. China E-mail: xl@nn.cn
- Luukkanen, Viikki Tropical Resources Institute, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: ol@nn.fi
- Berninger, Département des sciences biologiques, Cp 8888 succ centre ville, Université du Québec à Montréal, Montréal (QC) H3C 3P8, Canada E-mail: fb@nn.ca
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Stenberg,
Department of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland
E-mail:
pauline.stenberg@helsinki.fi
- Rautiainen, Department of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland E-mail: mr@nn.fi
- Manninen, Finnish Meteorological Institute, Meteorological research, Ozone and UV radiation research, P.O. Box 503, FIN-00101 Helsinki, Finland E-mail: tm@nn.fi
- Voipio, Finnish Forest Research Institute, Suonenjoki Research Station, FIN-77600 Suonenjoki, Finland E-mail: pv@nn.fi
- Smolander, Finnish Forest Research Institute, Suonenjoki Research Station, FIN-77600 Suonenjoki, Finland E-mail: hs@nn.fi
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Aphalo,
Faculty of Forestry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland; Current address Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, FIN-40351 Jyväskylä, Finland.
E-mail:
pedro.aphalo@jyu.fi
- Schoettle, Rocky Mountain Research Station, 240 West Prospect Road, Fort Collins, CO 80526, USA E-mail: aws@nn.us
- Lehto, Faculty of Forestry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland E-mail: tl@nn.fi
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Farquhar,
Cooperative Research Centre for Greenhouse Accounting and Environmental Biology Group, Research School of Biological Sciences, Australian National University, ACT 2601, Australia
E-mail:
farquhar@rsbs.anu.edu.au
- Buckley, Cooperative Research Centre for Greenhouse Accounting and Environmental Biology Group, Research School of Biological Sciences, Australian National University, ACT 2601, Australia E-mail: tnb@nn.au
- Miller, Research School of Biological Sciences, Australian National University, ACT 2601, Australia E-mail: jmm@nn.au
- Mussche, Laboratory of Forestry, Ghent University, Geraardsbergse Steenweg 267, B-9090 Melle, Belgium E-mail: sm@nn.be
- Samson, Laboratory of Plant Ecology, Ghent University, Coupure Links 653, B-9000 Gent, Belgium E-mail: rs@nn.be
- Nachtergale, Laboratory of Forestry, Ghent University, Geraardsbergse Steenweg 267, B-9090 Melle, Belgium E-mail: ln@nn.be
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De Schrijver,
Laboratory of Forestry, Ghent University, Geraardsbergse Steenweg 267, B-9090 Melle, Belgium
E-mail:
An.Deschrijver@rug.ac.be
- Lemeur, Laboratory of Plant Ecology, Ghent University, Coupure Links 653, B-9000 Gent, Belgium E-mail: rl@nn.be
- Lust, Laboratory of Forestry, Ghent University, Geraardsbergse Steenweg 267, B-9090 Melle, Belgium E-mail: nl@nn.be
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Yu,
Department of Plant Biology, P.O. Box 27, FIN-00014 University of Helsinki, Finland
E-mail:
qibin.yu@helsinki.fi
Category : Review article
Trees are particularly susceptible to climate change due to their long lives and slow dispersal. However, trees can adjust the timing of their growing season in response to weather conditions without evolutionary change or long-distance migration. This makes understanding phenological cueing mechanisms a critical task to forecast climate change impacts on forests. Because of slow data accumulation, unconventional and repurposed information is valuable in the study of phenology. Here, I develop and use a framework to interpret what phenological patterns among provenances of a species in a common garden reveal about their leafing cues, and potential climate change responses. Species whose high elevation/latitude provenances leaf first likely have little chilling requirement, or for latitude gradients only, a critical photoperiod cue met relatively early in the season. Species with low latitude/elevation origins leafing first have stronger controls against premature leafing; I argue that these species are likely less phenologically flexible in responding to climate change. Among published studies, the low to high order is predominant among frost-sensitive ring-porous species. Narrow-xylemed species show nearly all possible patterns, sometimes with strong contrasts even within genera for both conifers and angiosperms. Some also show complex patterns, indicating multiple mechanisms at work, and a few are largely undifferentiated across broad latitude gradients, suggesting phenotypic plasticity to a warmer climate. These results provide valuable evidence on which temperate and boreal tree species are most likely to adjust in place to climate change, and provide a framework for interpreting historic or newly-planted common garden studies of phenology.
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Salk,
Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, P.O. Box 49, SE- 230 53 Alnarp, Sweden; Faculty of International Studies, Utsunomiya University, 350 Minemachi, Utsunomiya-shi, Tochigi 321-8505 Japan; Institute for Globally Distributed Open Research and Education (IGDORE)
E-mail:
carl.salk@slu.se
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Lilja,
Finnish Forest Research Institute, Vantaa, Finland
E-mail:
arja.lilja@metla.fi
- Poteri, Finnish Forest Research Institute, Suonenjoki, Finland E-mail: mp@nn.fi
- Petäistö, Finnish Forest Research Institute, Suonenjoki, Finland E-mail: rlp@nn.fi
- Rikala, Finnish Forest Research Institute, Suonenjoki, Finland E-mail: rr@nn.fi
- Kurkela, Finnish Forest Research Institute, Vantaa, Finland E-mail: tk@nn.fi
- Kasanen, University of Helsinki, Department of Forest Sciences, Helsinki, Finland E-mail: rk@nn.fi
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Givnish,
Dept of Botany, University of Wisconsin, Madison, WI 53706, USA
E-mail:
givnish@facstaff.wisc.edu
Category : Research note
Foliage spectra form an important input to physically-based forest reflectance models. However, little is known about geographical variability of coniferous needle spectra. In this research note, we present an assessment of the geographical variability of Norway spruce (Picea abies (L.) H. Karst.) needle albedo, reflectance, and transmittance spectra across three study sites covering latitudes of 49–62°N in Europe. All spectra were measured and processed using exactly the same methodology and parameters, which guarantees reliable conclusions about geographical variability. Small geographical variability in Norway spruce needle spectra was observed, when compared to variability observed between previous measurement campaigns (employing slightly varying measurement and processing parameters), or to variability between plant functional types (broadleaved vs. coniferous). Our results suggest that variability of needle spectra is not a major factor introducing geographical variability to forest reflectance. The results also highlight the importance of harmonizing measurement protocols when collecting needle spectral libraries. Furthermore, the data collected for this study can be useful in studies where accurate information on spectral differences between broadleaved and coniferous tree foliage is needed.
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Hovi,
Aalto University, School of Engineering, Department of Built Environment, P.O. Box 14100, FI-00760 Aalto, Finland
https://orcid.org/0000-0002-4384-5279
E-mail:
aarne.hovi@aalto.fi
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Lukeš,
Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, 603 00 Brno, Czech Republic
https://orcid.org/0000-0002-3707-6557
E-mail:
lukes.p@czechglobe.cz
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Homolová,
Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, 603 00 Brno, Czech Republic
https://orcid.org/0000-0001-7455-2834
E-mail:
homolova.l@czechglobe.cz
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Juola,
Aalto University, School of Engineering, Department of Built Environment, P.O. Box 14100, FI-00760 Aalto, Finland
https://orcid.org/0000-0002-6050-7247
E-mail:
jussi.juola@aalto.fi
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Rautiainen,
Aalto University, School of Engineering, Department of Built Environment, P.O. Box 14100, FI-00760 Aalto, Finland; Aalto University, School of Electrical Engineering, Department of Electronics and Nanoengineering, P.O. Box 15500, FI-00760 Aalto, Finland
https://orcid.org/0000-0002-6568-3258
E-mail:
miina.a.rautiainen@aalto.fi
Terrestrial laser scanning (TLS) provides a unique opportunity to study forest canopy structure and its spatial patterns such as foliage quantity and dispersal. Using TLS point clouds for estimating leaf area density with voxel-based methods is biased by the physical dimensions of laser beams, which violates the common assumption of beams being infinitely thin. Real laser beams have a footprint size larger than several millimeters. This leads to difficulties in estimating leaf area density from light detection and ranging (LiDAR) in vegetation, where the target objects can be of similar or even smaller size than the beam footprint. To compensate for this bias, we propose a method to estimate the per-pulse cover fraction, defined as the fraction of laser beams’ footprint area that is covered by vegetation targets, using the LiDAR return intensity and an experimental calibration measurement. We applied this method to a Leica P40 single-return instrument, and report our experimental results. We found that conifer foliage had a lower average per-pulse cover fraction than broadleaved foliage, indicating an increased number of partial hits in conifer foliage. We further discuss limitations of our method that stem from unknown target properties that influence the LiDAR return intensity and highlight potential ways to overcome the limitations and manage the remaining uncertainty. Our method’s output, the per-beam cover fraction, may be useful in a weight function for methods that estimate leaf area density from LiDAR point clouds.
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Schraik,
Aalto University, School of Engineering, Department of Built Environment, P.O. Box 14100, FI-00076 Aalto, Finland;
https://orcid.org/0000-0002-7794-3918
E-mail:
daniel.schraik@aalto.fi
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Hovi,
Aalto University, School of Engineering, Department of Built Environment, P.O. Box 14100, FI-00076 Aalto, Finland;
https://orcid.org/0000-0002-4384-5279
E-mail:
aarne.hovi@aalto.fi
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Rautiainen,
Aalto University, School of Engineering, Department of Built Environment, P.O. Box 14100, FI-00076 Aalto, Finland; Aalto University, School of Electrical Engineering, Department of Electronics and Nanoengineering, P.O. Box 14100, FI-00076 Aalto, Finland
https://orcid.org/0000-0002-6568-3258
E-mail:
miina.a.rautiainen@aalto.fi
European beech (Fagus sylvatica L.) forests have a long history of coppicing, but the majority of formerly managed coppices are currently under conversion to high forest. The long time required to achieve conversion requires a long-term perspective to fully understand the implication of the applied conversion practices. In this study, we showed results from a long-term (1992–2014) case-study comparing two management options (natural evolution and periodic thinning) in a beech coppice in conversion to high forest. Leaf area index, litter production, radiation transmittance and growth efficiency taken as relevant stand descriptors, were estimated using both direct and indirect optical methods. Overall, results indicated that beech coppice showed positive and prompt responses to active conversion practices based on periodic medium-heavy thinning. A growth efficiency index showed that tree growth increased as the cutting intensity increased. Results from the case study supported the effectiveness of active conversion management from an economic (timber harvesting) and ecological (higher growth efficiency) point of view.
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Chianucci,
Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria – Forestry Research Centre, viale Santa Margherita 80, 52100 Arezzo, Italy
http://orcid.org/0000-0002-5688-2060
E-mail:
fchianucci@gmail.com
- Salvati, Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria – Research Centre for the Soil-Plant System, via della Navicella 2–4, 00184 Roma, Italy E-mail: bayes00@yahoo.it
- Giannini, Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria – Forestry Research Centre, viale Santa Margherita 80, 52100 Arezzo, Italy E-mail: tessa.giannini@entecra.it
- Chiavetta, Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria – Forestry Research Centre, viale Santa Margherita 80, 52100 Arezzo, Italy E-mail: ugo.chiavetta@entecra.it
- Corona, Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria – Forestry Research Centre, viale Santa Margherita 80, 52100 Arezzo, Italy E-mail: piermaria.corona@unitus.it
- Cutini, Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria – Forestry Research Centre, viale Santa Margherita 80, 52100 Arezzo, Italy E-mail: andrea.cutini@entecra.it
-
Boratynski,
Polish Academy of Sciences, Institute of Dendrology, 5 Parkowa str., 62-035 Kórnik, Poland
E-mail:
borata@man.poznan.pl
- Marcysiak, Kazimierz Wielki University, Institute of Biology and Environment Protection, 12 Ossolinskich str., 85-064 Bydgoszcz, Poland E-mail: km@nn.pl
- Lewandowska, Kazimierz Wielki University, Institute of Biology and Environment Protection, 12 Ossolinskich str., 85-064 Bydgoszcz, Poland E-mail: al@nn.pl
- Jasinska, Polish Academy of Sciences, Institute of Dendrology, 5 Parkowa str., 62-035 Kórnik, Poland E-mail: aj@nn.pl
- Iszkulo, Polish Academy of Sciences, Institute of Dendrology, 5 Parkowa str., 62-035 Kórnik, Poland E-mail: gi@nn.pl
- Burczyk, Kazimierz Wielki University, Institute of Biology and Environment Protection, 12 Ossolinskich str., 85-064 Bydgoszcz, Poland E-mail: jb@nn.pl
