Current issue: 57(2)

Under compilation: 57(3)

Scopus CiteScore 2021: 2.8
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Silva Fennica 1926-1997
Acta Forestalia Fennica

Articles containing the keyword 'intensity'

Category: Article

article id 5597, category Article
John C. Brissette. (1996). Effects of intensity and frequency of harvesting on abundance, stocking and composition of natural regeneration in the Acadian forest of eastern North America. Silva Fennica vol. 30 no. 2–3 article id 5597.
Keywords: thinning; silviculture; North America; United States; natural regenration; harvest intensity; partial harvest; repeated harvests
Abstract | View details | Full text in PDF | Author Info

In a silviculture experiment in east-central Maine, USA, natural regeneration was sampled to measure the effects of: (1) a range of partial harvest intensities, and (2) repeated partial harvest at one intensity. Under the first objective, five treatments were compared with residual basal areas ranging from 15 to 24 m2 ha-1 for trees ≥1.3 cm diameter at breast height. For the second objective, regeneration was evaluated after four harvests at 5-year intervals. Prior to harvests, the overstory of all the treated stands was dominated by Tsuga canadensis (L.) Carr., Picea spp. A Dietr., and Abies balsamea (L.) Mill. Eleven species or species groups were identified among the regeneration: A. balsamea, T. canadensis, Picea spp., Thuja occidentalis L., Pinus spp. L., Betula papyrifera Marsh., Acer rubrum L., Betula populifolia Marsh., Populus spp. L., Fagus grandifolia Ehrh. and Prunus serotina Ehrh. Regeneration abundance was measured as counts of seedlings or sprouts taller than 15 cm but with diameters less than 1.3 cm at breast height (1.37 m). Regardless of harvest treatment, total regeneration was profuse, ranging from over 25,000 to nearly 80,000 trees ha-1. Regeneration was dominated by conifers with a total angiosperm component of 10 to 52 percent approximately 5 years after harvest and 11 to 33 percent after 10 years. Consequently, in forests of similar species composition, tree regeneration following partial harvests should be sufficiently abundant with an array of species to meet a variety of future management objectives.

  • Brissette, E-mail: jb@mm.unknown (email)
article id 5477, category Article
Martti Saarilahti. (1992). Skidding by sulky - a literature study. Silva Fennica vol. 26 no. 2 article id 5477.
Keywords: work study; production; ergonomics; forest work; labour-intensity; sulkies
Abstract | View details | Full text in PDF | Author Info

Speed and load sizes presented in three study reports on sulky skidding were compared with estimates based on ergonomic models. Speed and load size estimates were closely correlated with the observed values, when a 400 W energy expenditure of the subject was used. This corresponds to less than half of his submaximal oxygen intake and matches well with the heart rate given in one of the time studies. It seems possible to develop methods for evaluating the work pace/production rate for sulky skidding in varying terrain conditions.

The PDF includes an abstract in Finnish.

  • Saarilahti, E-mail: ms@mm.unknown (email)
article id 5452, category Article
Riitta Höyhtyä, Heikki Hänninen. (1991). Effect of photon flux density on bud dormancy release in Norway spruce seedlings. Silva Fennica vol. 25 no. 3 article id 5452.
Keywords: Picea abies; dormancy; seedlings; buds; light intensity; chilling requirement; annual habit; development
Abstract | View details | Full text in PDF | Author Info

The effect of photon flux density on bud dormancy release in two-year-old seedlings of Norway spruce (Picea abies (L.) H. Karst.) was examined. The seedlings were first chilled for 0–21 weeks under natural conditions and then forced in a warm greenhouse either in low (15 μEm-2s-1) or in high (300 μEm-2s-1) photon flux density. Occurrence of bud burst was observed in the forcing conditions, and the observations were used for estimating the cumulative frequency distribution of the chilling requirement for growth competence. The estimated distribution had greater variance in the low photon flux density than in the high photon flux density forcing. This finding suggests that unnaturally low photon flux densities during forcing may yield overestimates of the genetic within-population variation in the chilling requirement for growth competence.

The PDF includes an abstract in Finnish.

  • Höyhtyä, E-mail: rh@mm.unknown (email)
  • Hänninen, E-mail: hh@mm.unknown
article id 5370, category Article
Harri Rantonen, Juhani Päivänen. (1989). Kasvatusmetsien metsänhoidollinen tila ojitusalueilla puunkorjuun jälkeen. Silva Fennica vol. 23 no. 1 article id 5370.
English title: Silvicultural condition of tree stands after thinning on drained peatlands.
Original keywords: metsänhoito; harvennushakkuu; puunkorjuu; turvemaat; ojitetut suot; harvennusvoimakkuus
English keywords: forest management; harvesting; forest drainage; silviculture; drained peatland; thinning intensity
Abstract | View details | Full text in PDF | Author Info

The area of stands studied by line plot survey was 594 ha. On the basis of the length of the inventory line the estimated proportion of harvesting strips was 14% and that of ditch openings 6% of the area. The calculated strip road spacing was 29 m. The option of the minimum diameter made it difficult to use the number of stems as criterion for thinning intensity. Thinning intensity evaluated according to the basal area had been stronger than recommended with low values of dominant height and milder with high values. The estimated removal according to stumps was 38 m3/ha on the average between the strips. The real removal has, however, been larger than that, as the strip road openings are made in connection with the first thinning.

The PDF includes an abstract in English.

  • Rantonen, E-mail: hr@mm.unknown (email)
  • Päivänen, E-mail: jp@mm.unknown
article id 5227, category Article
Harri Vasander, Tapio Lindholm. (1985). Tulen voimakkuus ja maanpinnan lämpötila kulotuksen aikana. Silva Fennica vol. 19 no. 1 article id 5227.
English title: Fire intensities and surface temperatures during prescribed burning.
Keywords: regeneration; slash; prescribed burning; logging waste; controlled burning; surface temperatures; fire intensity
Abstract | View details | Full text in PDF | Author Info

Surface temperature during two prescribed burnings were measured in 1983 in Evo, Southern Finland. Surface temperatures in relation to the amount of slash burned, energy released during the fires, and the fire intensities were studied. The fire intensity was also measured during a third burn. The Lake Nimetön site was burned int the end of May. Due to the uneven distribution of slash, colonization by Calamagrostis arundinacea and the spring moisture, the burning was very uneven. Surface temperatures varied between 410–809°C and the intensity of fire was low (range 0–900 kW/m).

The fire intensity on the other sites burned in May was also low (880 kW/m). During the burn in August the surface temperatures varied between 701–869°C and the intensity of fire was moderate (1,170 kW/m). Slash was burned more evenly and more thoroughly due to the dryness of the site and slash and the fact that grasses and other herbs were not abundant.

The PDF includes a summary in Finnish.

  • Vasander, E-mail: hv@mm.unknown (email)
  • Lindholm, E-mail: tl@mm.unknown
article id 4964, category Article
Seppo Kellomäki, Pertti Hari, Eero Väisänen. (1977). Annual production of some forest mosses as a function of light available for photosynthesis. Silva Fennica vol. 11 no. 1 article id 4964.
Keywords: photosynthesis; stand density; light intensity; Hylocomnium splendens; mosses; Dicranum polysetum; Pleurozium schreberi
Abstract | View details | Full text in PDF | Author Info

The aim of the present paper was to study the annual production of Pleurozium schreberi (Brid.) Mitt., Hylocomnium splendens (Hedw.) B.S.G and Dicranum polysetum Sw. as a function of light available for photosynthesis. The productivity of the above moss species is studied using the harvested quadrats method in Norway spruce (Picea abies) stands of the Myrtillus site type representing different stand density classes (basal area from 0 to 34 m2/ha) in Southern Finland.

The annual production of each species in different stands was correlated with the amount of light available for photosynthesis i.e. with the photosynthetic production. Functions for the dependence of productivity on light conditions were produced for each species. The individual functions and their ecological significance is discussed. The adaptation of each species to low light intensity is evident since no meaningful addition to production takes place when the photosynthetic light ratio reaches values greater than 0.3–0.4. In other words, the level of photosynthesis which is 30–40% of that possible in the open, provides sufficient supply of carbohydrates or the basic functions of the moss species studied. Pleurozium schreberi and Dicranum polysetum seem to have greater light requirements than Hylocomnium splendens.

The PDF includes a summary in Finnish.

  • Kellomäki, E-mail: sk@mm.unknown (email)
  • Hari, E-mail: ph@mm.unknown
  • Väisänen, E-mail: ev@mm.unknown
article id 4953, category Article
Seppo Kellomäki, Pertti Hari. (1976). Rate of photosynthesis of some forest mosses as a function of temperature and light intensity and effect of water content of moss cushion on photosynthetic rate. Silva Fennica vol. 10 no. 4 article id 4953.
Keywords: photosynthesis; temperature; light intensity; Pleurosium schreberi; Hylocomnium splendens; Dicranum undulatum; mosses; water deficiency
Abstract | View details | Full text in PDF | Author Info

The photosynthetic rate of Pleurosium schreberi (Willd.), Hylocomnium splendens (Hedw.) and Dicranum undulatum (Sw.) grown in plastic containers was monitored with infrared gas analyser in open air under natural weather conditions. It proved that the photosynthetic rate of wet moss cushions was satisfactorily predicted by temperature and light intensity. In dry moss cushions this kind of model gave too high an estimate for photosynthetic rate. Water requirements of each moss species were found to be moderate, and water content of moss cushions limited photosynthetic rate only under serious water deficiency.

The PDF includes a summary in Finnish.

  • Kellomäki, E-mail: sk@mm.unknown (email)
  • Hari, E-mail: ph@mm.unknown
article id 4937, category Article
Pertti Hari, Mikko Huhtamaa, Paavo Pelkonen, Veli Pohjonen, Raimo Salminen. (1976). A new approach for measuring light inside the canopy in photosynthesis studies. Silva Fennica vol. 10 no. 2 article id 4937.
Keywords: photosynthesis; canopy; light intensity; measuring methods
Abstract | View details | Full text in PDF | Author Info

Light intensity inside the canopy varies considerably both in space and time. A new apparatus was developed which is disturbed as little as possible by the above-mentioned variation. The construction is based on the linear relationships between light intensity (measured using silicon diodes) and photosynthesis. This procedure permits linear operations (summing and integration) to be carried out on the output of the diodes without any loss of accuracy. There are five diodes in each assimilation chamber. A model, in which the independent variables include ligth, measured with the present equipment, and temperature, fits the photosynthetic rates well even inside the canopy.

The PDF includes a summary in Finnish.

  • Hari, E-mail: ph@mm.unknown (email)
  • Huhtamaa, E-mail: mh@mm.unknown
  • Pelkonen, E-mail: pp@mm.unknown
  • Pohjonen, E-mail: vp@mm.unknown
  • Salminen, E-mail: rs@mm.unknown
article id 4770, category Article
Kustaa Seppälä. (1968). Ennakkotuloksia suometsiköiden ojituksen jälkeisestä kehityksestä ja siihen vaikuttavista tekijöistä. Silva Fennica vol. 2 no. 3 article id 4770.
English title: Preliminary results of post-drainage development of peatland stands in Finland.
Original keywords: kasvu; suometsät; turvekankaat; ojitetut suot; kuivatustehokkuus; ojaväli
English keywords: drained peatlands; increment; draining intensity; ditch interval; drainage effect; stand recovery
Abstract | View details | Full text in PDF | Author Info

The present paper is a preliminary report of a project designed to determine the order of profitability of various forest improvement measures – seeding and planting, drainage, and fertilization – in various types of stands and in different parts of the country on drained peatlands. Sample plot data on the effect of draining on increment was derived from areas drained 28– 36 years ago. The study was carried out in the southern half of Finland.

The observations on increment changes are based on two measurements of the sample stands 12 years apart. Supplementary calculations indicate that the stands on drained peatland, depending on site quality and tree species, have either continued to grow like mineral-soil sites of similar fertility or have somewhat increased their growth rate.

The effect of draining intensity was studied using strip measurements. It was found that both the total amount of wood produced (current stand + cutting removal + natural removal) and the current annual volume increment for the 5-year period systematically decrease as the ditch interval increases. The decrease is, however, relatively slight. In Eriophorum vaginatum pine swamps, the total amount of wood produced and the increment show a decrease of ca. 20% with an increase in ditch interval from 20 to 60 metres. In other sites, the decrease is ca. 5-10%

It can be concluded that if the increase in ditch interval do not result in considerably poorer timber assortment distributions than indicates by stand production and increment, it is profitable to pan for a relatively large ditch interval and a slightly smaller than maximum wood production. Supplementary data and check calculations may cause some changes in these preliminary results.

The PDF includes a summary in English.

  • Seppälä, E-mail: ks@mm.unknown (email)

Category: Article

article id 7559, category Article
Kustaa Seppälä. (1972). Ditch spacing as a regulator of post-drainage stand development in Norway spruce and in pine swamps. Acta Forestalia Fennica vol. 0 no. 125 article id 7559.
Keywords: drained peatlands; growth; draining intensity; ditch spacing; volume increment
Abstract | View details | Full text in PDF | Author Info

The paper is based on data collected from 411 sample plots in various parts of Finland situated on peatlands which had been drained in the 1930's. The purpose of the study was to determine the influence of ditch spacing on the volume, increment and structure of timber crops growing on drained peatlands. The ditches had been spaced 70–90 m apart, and the sample plots were placed strip wise along the ditches.

The results of the study indicate that the influence of ditch spacing on both the total volume and the volume increment is greater, the poorer the site. On the other hand, the influence of ditch spacing on the structure of the stand as described by means of the mean diameter as weighted by the basal area, seems to be of similar magnitude in all the sites covered by the study.

Generally speaking, the influence of ditch spacing on stand development is surprisingly small, even in extreme cases. The total volume and the increment of the growing stock decrease by about 20% when the ditch spacing increases from 20 to 60 m, the corresponding decrease in the mean diameter having a magnitude of 10%. This was interpreted to be due to the fact that the main part of the superior growth along the margin of the ditch is spent in compensating for the space lost in the area taken up by the ditches.

On the basis of the results obtained it was concluded that the best solution in forest drainage from the economic viewpoint is to employ relatively wide ditch spacings, which leads to a rate of stand development somewhat below the potential.

The PDF includes a summary in Finnish.

  • Seppälä, E-mail: ks@mm.unknown (email)

Category: Research article

article id 1211, category Research article
Xiao Chen, Deborah Page-Dumroese, Ruiheng Lv, Weiwei Wang, Guolei Li, Yong Liu. (2014). Interaction of initial litter quality and thinning intensity on litter decomposition rate, nitrogen accumulation and release in a pine plantation. Silva Fennica vol. 48 no. 4 article id 1211.
Keywords: litter quality; litter decomposition; nitrogen cycling; thinning intensity; Pinus tabulaeformis
Highlights: Litter quality and thinning showed an interaction on one year litter decomposition rates, N accumulation, and net N release; N accumulated until the underlying critical acid-unhydrolyzable residue to nitrogen ratio (approximately 57–69) was met; Increased N concentration in litter and thinning intensity induced rapid litter decomposition and N cycling in coniferous plantation with a slow decomposition rate.
Abstract | Full text in HTML | Full text in PDF | Author Info
Thinning alters litter quality and microclimate under forests. Both of these two changes after thinning induce alterations of litter decomposition rates and nutrient cycling. However, a possible interaction between these two changes remains unclear. We placed two types of litter (LN, low N concentration litter; HN, high N concentration litter) in a Chinese pine (Pinus tabulaeformis Carrière) plantation under four thinning treatments to test the impacts of litter quality, thinning or their combination on decomposition rate and N cycling. In our study, N was accumulated to approach an underlying critical acid-unhydrolyzable residue to nitrogen ratio (approximately 57–69) in litter. Moreover, an interaction between litter quality and thinning on decomposition rates, N accumulation and net release did exist. On one hand, one year decomposition rate of LN was elevated after thinning while that of HN remained the same or even lower (under light thinning); N accumulation of LN declined with light thinning and was restored with the increase of thinning intensity whereas that of HN did not decline with thinning and increased under heavy thinning; Net N release from LN was only found in light and heavy thinning while that from HN was found in all treatments, moreover net N release from LN and HN were both elevated under heavy thinning. On the other hand, HN decomposed faster, accumulated less and released more N than LN did under all treatments. Generally, high N concentration in litter and high-intensity thinning can lead to rapid litter decomposition and N cycling in coniferous plantations.
  • Chen, Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing, 100083, China E-mail:
  • Page-Dumroese, U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, 1221 South Main Street, Moscow, ID 83843, USA E-mail:
  • Lv, College of Plant Science and Technology, Tarim University, Alar Xinjiang, 843300, China E-mail:
  • Wang, Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing, 100083, China E-mail:
  • Li, Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing, 100083, China E-mail:
  • Liu, Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing, 100083, China E-mail: (email)
article id 156, category Research article
Ilkka Korpela, Hans Ole Ørka, Matti Maltamo, Timo Tokola, Juha Hyyppä. (2010). Tree species classification using airborne LiDAR – effects of stand and tree parameters, downsizing of training set, intensity normalization, and sensor type. Silva Fennica vol. 44 no. 2 article id 156.
Keywords: airborne laser scanning; ALS; laser; Optech ALTM3100; Leica ALS50-II; canopy; crown modeling; monoplotting; backscatter amplitude; intensity; discriminant analysis
Abstract | View details | Full text in PDF | Author Info
Tree species identification constitutes a bottleneck in remote sensing-based forest inventory. In passive images the differentiating features overlap and bidirectional reflectance hampers analysis. Airborne LiDAR provides radiometric and geometric information. We examined the single-trees-level response of two LiDAR sensors in over 13 000 forest trees in southern Finland. We focused on the commercially important species. Our aims were to 1) explore the relevant LiDAR features and study their dependencies on stand and tree variables, 2) examine two sensors and their fusion, 3) quantify the gain from intensity normalizations, 4) examine the importance of the size of the training set, and 5) determine the effects of stand age and site fertility. A set of 570 semiurban broad-leaved trees and exotic conifers was analyzed to 6) examine the LiDAR signal in the economically less important species. An accuracy of 88 90% was achieved in the classification of Scots pine, Norway spruce, and birch, using intensity variables. Spruce and birch showed the highest levels of confusion. Downsizing the training set from 30% to 2.5% of all trees had only a marginal effect on the performance of classifiers. The intensity features were dependent on the absolute and relative sizes of trees, especially for birch. The results suggest that leaf size, orientation, and foliage density affect the intensity, which is thus not affected by reflectance only. Some of the ecologically important species in Finland may be separable, since they gave rise to high intensity values. Comparison of the sensors implies that performance of the intensity data for species classification varies between sensors for reasons that remained uncertain. Both range and gain receiver normalization improved species classification. Weighting of the intensity values improved the fusion of two LiDAR datasets.
  • Korpela, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: (email)
  • Ørka, Norwegian University of Life Sciences, Department of Ecology and Natural Resource Management, P.O.Box 5003, NO-1432 Ås, Norway E-mail:
  • Maltamo, University of Eastern Finland, School of Forest Science, P.O. Box 111, FI-80101 Joensuu, Finland E-mail:
  • Tokola, University of Eastern Finland, School of Forest Science, P.O. Box 111, FI-80101 Joensuu, Finland E-mail:
  • Hyyppä, Finnish Geodetic Institute, Department of Photogrammetry and Remote Sensing, P.O.Box 15, FI-02431 Masala, Finland E-mail:
article id 415, category Research article
Sandhya Samarasinghe, Don Kulasiri. (2004). Stress intensity factor of wood from crack-tip displacement fields obtained from digital image processing. Silva Fennica vol. 38 no. 3 article id 415.
Keywords: Pinus radiata; wood; fracture toughness; stress intensity factor; digital image correlation; orthotropic fracture theory
Abstract | View details | Full text in PDF | Author Info
Stress intensity factor of radiata pine (Pinus radiata) in Tangential-Longitudinal opening mode was determined from crack-tip displacement fields obtained from digital image correlation in conjunction with orthotropic fracture theory. For lower loads, experiments agreed with the linear elastic fracture theory but for higher loads, stress intensity factor and load relationship was nonlinear. For 41% of the specimens tested, tip-displacement based stress intensity factor agreed with that based on the ASTM standard formula for lower loads but deviated for higher loads closer to failure. The tip displacement plots showed that the nonlinear behaviour is due to large displacements which we attributed to large plastic deformations and/or micro-cracking in this region. The other 59% specimens showed a similar trend except that the crack-tip based stress intensity factor was consistently higher than the value obtained from the standard formula. The fracture toughness from tip displacements was larger than the standard values for all specimens and the two were related by a logarithmic function with an R2 of 0.61. The study also established that fracture toughness increases with the angle of inclination of the original crack plane to the Radial Longitudinal plane.
  • Samarasinghe, Lincoln University, P.O. Box 84, Canterbury, New Zealand E-mail:
  • Kulasiri, Lincoln University, P.O. Box 84, Canterbury, New Zealand E-mail: (email)

Category: Review article

article id 1416, category Review article
Ulf Sikström, Hannu Hökkä. (2015). Interactions between soil water conditions and forest stands in boreal forests with implications for ditch network maintenance. Silva Fennica vol. 50 no. 1 article id 1416.
Keywords: peatland; forest drainage; conifers; tree growth; drainage intensity; ditch deterioration; forest water use; ground-water table; profitability
Highlights: Ditch network maintenance (DNM) may influence soil water conditions less than initial ditching due to reduced hydraulic conductivity of the peat; Stand stocking and management substantially influence soil-water conditions; DNM can lower the GWL and increase tree growth; DNM growth responses of 0.5–1.8 m3 ha–1 yr–1 during 15–20-years in Scots pine peatland stands reported; Greatest need for DNM in the early phase of a stand rotation; Need for better understanding of the link between soil water and tree growth.
Abstract | Full text in HTML | Full text in PDF | Author Info

At sites with either peat or mineral soils in large areas of boreal forests, high soil-water contents hamper tree growth and drainage can significantly increase growth. Hence, areas covering about 15 × 106 ha of northern peatlands and wet mineral soils have been drained for forestry purposes. Usually ditches gradually deteriorate, thus reducing their functionality as drains, and ditch-network maintenance (DNM) might be needed to maintain stand growth rates enabled by the original ditching. This article reviews current knowledge on establishing the need for DNM in boreal forest stands, subsequent growth responses, and the financial outcome of the activity. The issues covered in the review are: (i) ditching, changes in ditches over time and the need for DNM; (ii) interactions between soil water and both stand properties and stand management; (iii) ground-water level (GWL) and tree growth responses to DNM; and (iv) financial viability of DNM. Conclusions about the current understanding of issues related to DNM are drawn and implications for DNM in practice are summarized. Finally, gaps in knowledge are identified and research needs are suggested.

  • Sikström, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: (email)
  • Hökkä, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, P.O. Box 16, FI-96301 Rovaniemi, Finland E-mail:

Category: Research note

article id 10533, category Research note
Daniel Schraik, Aarne Hovi, Miina Rautiainen. (2021). Estimating cover fraction from TLS return intensity in coniferous and broadleaved tree shoots. Silva Fennica vol. 55 no. 4 article id 10533.
Keywords: terrestrial laser scanning; leaf area; lidar intensity; physically-based; voxel
Highlights: We developed a method to obtain the fraction of TLS pulses’ footprint area covered by a target’s projection area; We tested our method with shoots of Norway spruce, Scots pine and silver birch; We provide a physically-based framework related to unmeasured variables, and provide a robust statistical framework to deal with uncertainty.
Abstract | Full text in HTML | Full text in PDF | Author Info

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.

  • Schraik, Aalto University, School of Engineering, Department of Built Environment, P.O. Box 14100, FI-00076 Aalto, Finland; ORCID E-mail: (email)
  • Hovi, Aalto University, School of Engineering, Department of Built Environment, P.O. Box 14100, FI-00076 Aalto, Finland; ORCID E-mail:
  • 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 ORCID E-mail:

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