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Silva Fennica 1926-1997
1990-1997
1980-1989
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Acta Forestalia Fennica
1953-1968
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1913-1932

Articles containing the keyword 'spatial analysis'.

Category: Research article

article id 7746, category Research article
Jānis Donis, Māra Kitenberga, Guntars Šņepsts, Roberts Matisons, Juris Zariņš, Āris Jansons. (2017). The forest fire regime in Latvia during 1922–2014. Silva Fennica vol. 51 no. 5 article id 7746. https://doi.org/10.14214/sf.7746
Highlights: Climate effects and human influence on forest fire activity in Latvia was assessed using time-series analysis; Drought conditions during summer season had the strongest effect on fire activity of tested climatic variables; Negative trends and spatial distribution pattern of fire activity suggests of prevailing human influence on forest fire regime over the 20th century.

Fire as disturbance of forests has an important ecological and economical role in boreal and hemiboreal forests. The occurrence of forest fires is both climatically and anthropogenically determined and shifts in fire regimes are expected due to climate change. Although fire histories have been well documented in boreal regions, there is still insufficient information about fire occurrence in the Baltic States. In this study, spatio-temporal patterns and climatic drivers of forest fires were assessed by means of spatial and time-series analysis. The efficiency of Canadian Fire Weather (FWI) indices as indicators for fire activity was tested. The study was based on data from the literature, archives, and the Latvian State Forest service database. During the period 1922–2014, the occurrence and area affected by forest fires has decreased although the total area of forest land has nearly doubled, suggesting improvement of the fire suppression system as well as changes in socioeconomic situation. The geographical distribution of forest fires revealed two pronounced clusters near the largest cities of Riga and Daugavpils, suggesting dominance of human causes of ignitions. The occurrence of fires was mainly influenced by drought. FWI appeared to be efficient in predicting the fire occurrence: 23–34% of fires occurred on days with a high or extremely high fire danger class, which overall had a relative occurrence of only 4.3–4.6%. During the 20th century, the peak of fire activity shifted from May to April, probably due to global warming and socioeconomic reasons. The results of this study are relevant for forest hazard mitigation and development of fire activity prediction system in Latvia.

  • Donis, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: janis.donis@silava.lv
  • Kitenberga, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: mara.kitenberga@gmail.com (email)
  • Šņepsts, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: guntars.snepsts@silava.lv
  • Matisons, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: robism@inbox.lv
  • Zariņš, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: juris.zarins@silava.lv
  • Jansons, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: aris.jansons@silava.lv

Category: Article

article id 5598, category Article
Timo Kuuluvainen, Kari Leinonen, Markku Nygren, Antti Penttinen. (1996). Statistical opportunities for comparing stand structural heterogeneity in managed and primeval forests: an example from boreal spruce forest in southern Finland. Silva Fennica vol. 30 no. 2–3 article id 5598. https://doi.org/10.14214/sf.a9243

The horizontal and vertical stand structure of living trees was examined in a managed and in a primeval Norway spruce-dominated forest in Southern Finland. Tree size distributions (DBHs, tree height) were compared using frequency histograms. The vertical distribution of tree heights was illustrated as tree height plots and quantified as the tree height diversity (THD) using the Shannon-Weaver formula. The horizontal spatial pattern of trees was described with stem maps and quantified with Ripley's K-function. The spatial autocorrelation of tree sizes was examined with semivariogram analysis. In the managed forest the DBH and height distributions of trees were bimodal, indicating a two-layered vertical structure with a single dominant tree layer and abundant regeneration in the understory. The primeval forest had a much higher total number of trees which were rather evenly distributed in different diameter and tree height classes. The K-function summaries for trees taller than 15 m indicated that the primeval stand was close to complete random pattern. The managed stand was regular at small distances (up to 4 m). The semivariograms of tree sizes (DBH tree height) showed that the managed forest had a clear spatial dependence in tree sizes up to inter-tree distances of about 12 meters. In contrast, the primeval spruce forest had a variance peak at very short inter-tree distances (< 1 m) and only weak spatial autocorrelation at short inter-tree distances (1–5 m). Excluding the understory trees (h < 15 m) from the analysis drastically changed the spatial structure of the forest as revealed by semivariograms. ln general, the structure of the primeval forest was both horizontally and vertically more variable and heterogeneous compared to the managed forest. The applicability of the used methods in describing fine-scale forest structure i discussed.

  • Kuuluvainen, ORCID ID:E-mail:
  • Leinonen, ORCID ID:E-mail:
  • Nygren, ORCID ID:E-mail:
  • Penttinen, ORCID ID:E-mail:
article id 7673, category Article
Jimin Tan. (1992). Planning a forest road network by a spatial data handling-network routing system. Acta Forestalia Fennica no. 227 article id 7673. https://doi.org/10.14214/aff.7673

The basic objective in planning a forest road network is to minimize the total cost of terrain transportation, road transportation, road construction and maintenance by controlling the road location, road network density and road quality, besides environmental and ecological considerations. Studies on the optimization of forest road network have encountered difficulties in taking into account the spatial diversity of forest terrain and stands. The spatial data handling-network routing system developed in this study proves to be useful in assisting forest managers to carry out the planning of forest road networks by covering the spatial and economic analysis.

The PDF includes a summary in Finnish.

  • Tan, ORCID ID:E-mail:

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