Impact of stand structure on surface fire ignition potential in Picea abies and Pinus sylvestris forests in southern Finland

2005 ◽  
Vol 35 (2) ◽  
pp. 410-420 ◽  
Author(s):  
Heidi Tanskanen ◽  
Ari Venäläinen ◽  
Pasi Puttonen ◽  
Anders Granström
Keyword(s):  
Picea Abies ◽  
Pinus Sylvestris ◽  
Stand Structure ◽  
Weather Data ◽  
Stand Age ◽  
Small Scale ◽  
Age Classes ◽  
Area Index ◽  
Fire Weather Index ◽  
Fire Ignition

Forest fire ignition potential was investigated in Picea abies (L.) Karst. (Norway spruce) and Pinus sylvestris L. (Scots pine) dominated stands of 0, 15, 30–45, and 40–60 years of age. A series of small-scale (<0.5 m2) ignition tests were carried out in experimental plots on 61 different days in June, July, and August. Ignition success percentages were analyzed in relation to stand structural properties, preclassified stand types, and the output of the Canadian Fire Weather Index system. In addition, the number of average stand-type-specific fire days was estimated based on weather data (June–August) for southern Finland for the years 1991–2002. Factors in stand structure that significantly correlated with the ignition success percentage were canopy depth and leaf area index, the correlation coefficients being –0.575 (p < 0.005) and –0.582 (p < 0.005), respectively. In Pinus sylvestris dominated stands, ignition tests produced self-sustained surface fires in 32.0%, 24.0%, and 19.3% of cases in 0-, 15-, and 30- to 45-year age classes, respectively. In Picea abies dominated sites conditions were favorable for fire in 12.0% and 4.6% of trials in the 0- and 40- to 60-year age classes, respectively. The output of the FWI-system correlated well with the ignition success in June and July but poorly in August. Based on the 12-year time series analysis, there were on average per year 27, 18, and 14 potential fire days in 0-, 15-, and 30- to 45-year-old Pinus sylvestris stands, and 10 and 4 potential fire days in 0- and 40- to 60-year-old Picea abies stands, respectively. We concluded that the dominance of Picea abies or Pinus sylvestris and stand age appear to modify the ignition conditions significantly and should be used as threshold indicators in fire occurrence predictions.

Forest structure estimation and pattern exploration from discrete-return lidar in subalpine forests of the central Rockies

2008 ◽  
Vol 38 (8) ◽  
pp. 2081-2096 ◽  
Author(s):  
K. R. Sherrill ◽  
M. A. Lefsky ◽  
J. B. Bradford ◽  
M. G. Ryan
Keyword(s):  
Leaf Area ◽  
Forest Structure ◽  
Stand Structure ◽  
Forest Biomass ◽  
Canopy Structure ◽  
Primary Source ◽  
Subalpine Forest ◽  
Stand Age ◽  
Area Index ◽  
The North

This study evaluates the relative ability of simple light detection and ranging (lidar) indices (i.e., mean and maximum heights) and statistically derived canonical correlation analysis (CCA) variables attained from discrete-return lidar to estimate forest structure and forest biomass variables for three temperate subalpine forest sites. Both lidar and CCA explanatory variables performed well with lidar models having slightly higher explained variance and lower root mean square error. Adjusted R2 values were 0.93 and 0.93 for mean height, 0.74 and 0.73 for leaf area index, and 0.93 and 0.85 for all carbon in live biomass for the lidar and CCA explanatory regression models, respectively. The CCA results indicate that the primary source of variability in canopy structure is related to forest height, biomass, and total leaf area, and the second most important source of variability is related to the amount of midstory foliage and tree density. When stand age is graphed as a function of individual plot scores for canonicals one and two, there is a clear relationship with stand age and the development of stand structure. Lidar-derived biomass and related estimates developed in this work will be used to parameterize decision-support tools for analysis of carbon cycle impacts as part of the North American Carbon Program.

Butt rot incidence, causal fungi, and related yield loss in Picea abies stands of Latvia

2011 ◽  
Vol 41 (12) ◽  
pp. 2337-2345 ◽  
Author(s):  
N. Arhipova ◽  
T. Gaitnieks ◽  
J. Donis ◽  
J. Stenlid ◽  
R. Vasaitis
Keyword(s):  
Picea Abies ◽  
Species Composition ◽  
Tree Species ◽  
Yield Loss ◽  
Stand Age ◽  
Forest Site ◽  
Age Classes ◽  
Butt Rot ◽  
Forest Sites ◽  
Site Types

Root and butt rot is the most destructive disease of conifers in the Northern Hemisphere, but little is known about the dynamics of yield loss in stands of different ages, site types, and species composition. This study aimed to estimate butt rot incidence, causal fungi, and related wood yield loss in Picea abies (L.) H. Karst. stands in Latvia. A total of 24 745 stumps were examined on 318 forest sites, and 21.8% of them contained rot. There was a positive correlation between stand age and butt rot frequency. Proportion of other tree species in a stand had no influence on incidence of the rot, but significant differences were observed among different forest site types. The length of decay columns in 114 stems analysed was 6.6 ± 2.6 m on average. Based on the observed butt rot frequencies in Latvian P. abies stands of different age classes, volumes of decay-degraded wood in a fully stocked stand would comprise about 19.7 m3·ha–1 at the age of 40 years, 57.4 m3·ha–1 at 60 years, 54.9 m3·ha–1 at 80 years, 63.1 m3·ha–1 at 100 years, and 91.8 m3·ha–1 at 120 years, corresponding to 6%–16% of a total standing volume.

Leaf area and tree increment dynamics of even-aged and multiaged lodgepole pine stands in Montana

1999 ◽  
Vol 29 (6) ◽  
pp. 687-695 ◽  
Author(s):  
Cassandra L Kollenberg ◽  
Kevin L O'Hara
Keyword(s):  
Leaf Area ◽  
Pinus Contorta ◽  
Stand Structure ◽  
Lodgepole Pine ◽  
Stem Volume ◽  
Age Classes ◽  
Cross Sectional ◽  
Individual Tree ◽  
Area Index ◽  
Volume Increment

Age structure and distribution of leaf area index (LAI) of even and multiaged lodgepole pine (Pinus contorta var. latifolia Engelm.) stands were examined on three study areas in western and central Montana. Projected leaf area was determined based on a relationship with sapwood cross-sectional area at breast height. Stand structure and LAI varied considerably between individual plots. LAI and stand stem volume increment were significantly higher in multiaged than even-aged stands with the exception of one study area, which had higher volume increment in even-aged stands. Older cohorts and higher canopy strata generally had greater LAI than younger cohorts and lower strata. Ratios of stem volume increment to leaf area were used to assess stand, cohort, and individual tree vigor or growing space efficiency (GSE). Even-aged stands had significantly higher GSEs in individual study areas and overall than multiaged stands. Cohort GSE generally increased with increasing age of the cohort. Stand increment was weakly associated with stand LAI. Individual tree volume increment was strongly related to projected leaf area when stands were divided by age-classes or canopy strata. These results suggest separating these stands into components, such as age classes or canopy strata, and summing predicted increment for each component may provide more accurate prediction of stand increment than using whole-stand LAI.

Experimental fire behaviour in managed Pinus sylvestris and Picea abies stands of Finland

2007 ◽  
Vol 16 (4) ◽  
pp. 414 ◽  
Author(s):  
Heidi Tanskanen ◽  
Anders Granström ◽  
Markku Larjavaara ◽  
Pasi Puttonen
Keyword(s):  
Wind Speed ◽  
Picea Abies ◽  
Pinus Sylvestris ◽  
Risk Index ◽  
Fire Risk ◽  
Fire Spread ◽  
Fire Weather ◽  
Fire Behaviour ◽  
Fire Weather Index ◽  
Fuel Moisture Content

Fire behaviour characteristics were studied in managed Pinus sylvestris L. and Picea abies L. Karst stands in a series of field burning experiments. Stand characteristics, surface fuel moisture content, mid-flame wind speed, rates of spread, flame heights, and torching were recorded. The Canadian Forest Fire Weather Index System (FWI System) and Finnish Fire Risk Index (FFI) were used to evaluate burning conditions and analyse the observed fire behaviour. Mid-flame wind speed was a good predictor (R2 = 0.96 for exponential curve) of the fire spread rates. Torching formed the strongest correlation with the height of the dead branch limit. An increase in predicted fire weather hazard from FWI 4 to FWI 20 (FWI = the FWI code of the FWI System) increased burn coverage remarkably in 15–45-year-old Pinus stands and to a lesser extent in Pinus and Picea clear-cuts, but did not affect 40–60-year-old Picea stands. The FFI was unable to predict burn coverage or any other fire behaviour characteristics.

Predicting forest growth based on airborne light detection and ranging data, climate data, and a simplified process-based model

2013 ◽  
Vol 43 (4) ◽  
pp. 364-375 ◽  
Author(s):  
Sanna Härkönen ◽  
Timo Tokola ◽  
Petteri Packalén ◽  
Lauri Korhonen ◽  
Annikki Mäkelä
Keyword(s):  
Basal Area ◽  
Field Measurements ◽  
Forest Growth ◽  
Light Detection And Ranging ◽  
Weather Data ◽  
Stand Age ◽  
Climate Data ◽  
Light Detection ◽  
Area Index ◽  
Forest Inventories

Increasing use of airborne light detection and ranging (LiDAR) in forest inventories offers new possibilities to apply process-based forest models (PBM) in practice. We present a new approach, where a simplified PBM is run using inputs derived from the LiDAR data. The PBM was built by combining several existing models together, and it was tested with 52 Scots pine (Pinus sylvestris L.) dominated sample plots in Finland with the LiDAR (PBM_LIDAR) and field (PMB_FIELD) inputs. The results were compared with empirical growth predictions (EM_FIELD) and field reference growth. LiDAR-based stand variables (mean height of tree and crown base and leaf area index) were, on average, well in line with the field measurements. Basal area growth was slightly underestimated with the PBM_LIDAR (bias 4.1%, root mean square prediction error (RMSPE, 26.7%) and overestimated with the PBM_FIELD (bias –10.2%, RMSPE 33.3%), the EM_FIELD being the least biased (bias –1.9%, RMSPE of 24.6%). The bias varied with stand age and fertility. The dependence on field reference growth was highest with EM_FIELD and PBM_LIDAR (R2 = 0.47 and 0.34, respectively), and lowest with PBM_FIELD (R2 = 0.18). Despite several development needs, the approach is promising for easy incorporation of canopy and weather data into forest growth predictions.

scholarly journals Carbon stocks of homestead forests have a mitigation potential to climate change in Bangladesh

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tarit Kumar Baul ◽  
Tajkera Akhter Peuly ◽  
Rajasree Nandi ◽  
Lars Holger Schmidt ◽  
Shyamal Karmakar
Keyword(s):  
Species Diversity ◽  
Stand Structure ◽  
Diversity Index ◽  
Carbon Stocks ◽  
Small Scale ◽  
Species Diversity Index ◽  
C Stocks ◽  
Homestead Forests ◽  
C Stock ◽  
Low Altitude

AbstractA total of 176 homestead forests at three altitudes in the Chittagong Hill Tracts, Bangladesh were randomly surveyed to estimate carbon (C) stocks and how stand structure affects the biomass C. All woody vegetations were measured, and litter and soil (0–30 cm depth) were sampled. The tree biomass C stock in the top two altitude forests was up to 37–48% higher than in low altitude, owing to significantly higher tree density and species diversity. An increase in species diversity index by one unit increased the biomass stock by 23 Mg C ha−1. The C stock of litterfall in low altitude forests was 22–28% higher than in the top two altitude due to the deposition of litters downslope and deliberate use of mulch for soil improvement and conservation, resulting in up to 5% higher total soil C. The topsoil C was 10–25% higher than the deeper soil, depending on the altitude. The forest stored 89 Mg C ha−1, indicating a potential for C sequestration in trees outside forest. This study would help policymakers to strengthen the recognition of small-scale forests for mitigation in REDD + (reducing emissions from deforestation and forest degradation, the role of conservation, sustainable management of forests, and enhancement of forest carbon stocks) and support owners through C credits from sustainably managed forests.

scholarly journals The Difficulty of Predicting Eastern Spruce Dwarf Mistletoe in Lowland Black Spruce: Model Benchmarking in Northern Minnesota, USA

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 843
Author(s):  
Ella R. Gray ◽  
Matthew B. Russell ◽  
Marcella A. Windmuller-Campione
Keyword(s):  
Stand Structure ◽  
Black Spruce ◽  
Forest Health ◽  
Basal Area ◽  
Predictive Performance ◽  
Stand Age ◽  
Management Decisions ◽  
Dwarf Mistletoe ◽  
Growing Seasons ◽  
Model Interpretation

Insects, fungi, and diseases play an important role in forest stand development and subsequently, forest management decisions and treatments. As these disturbance agents commonly occur within and across landscapes, modeling has often been used to inform forest planning and management decisions. However, models are rarely benchmarked, leaving questions about their utility. Here, we assessed the predictive performance of a Bayesian hierarchical model through on–the-ground sampling to explore what features of stand structure or composition may be important factors related to eastern spruce dwarf mistletoe (Arceuthobium pusillum Peck) presence in lowland black spruce (Picea mariana (Mill.) B. S. P.). Twenty-five state-owned stands included in the predictive model were sampled during the 2019 and 2020 growing seasons. Within each stand, data related to the presence of eastern spruce dwarf mistletoe, stand structure, and species composition were collected. The model accurately predicted eastern spruce dwarf mistletoe occurrence for 13 of the 25 stands. The amount of living and dead black spruce basal area differed significantly based on model prediction and observed infestation, but trees per hectare, total living basal area, diameter at breast height, stand age, and species richness were not significantly different. Our results highlight the benefits of model benchmarking to improve model interpretation as well as to inform our understanding of forest health problems across diverse stand conditions.

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