Individual tree crown (ITC) techniques


Regrouping tree crowns into forest stands (or environmental strata) and obtaining detailed information about their content

Fig. a - Pseudo-colour infrared rendition of a sub-area of a Casi image (60 cm/pixel) of the Nahmint Lake species trial area in the central forest of Vancouver Island, British Columbia, Canada. The delineated areas (in white) correspond to stands judged relatively uniform by a forester. The training and testing areas used for the classification were delineated where species are known to be homogeneous. Their respective species and colours are: Douglas-fir (Pseudotsuga menziesii) in red, grand fir (Abies grandis) in green, amabilis fir (Abies amabilis) in blue, westerm redcedar (Thuja plicata) in orange, and western hemlock (Tsuga heterophylla) in yellow.
(a)
Fig. b - The individual tree crown (ITC) classification of Figure 3 and its computer generated forest stand outlines using the same colour  scheme as Figure 3.
(b)

 

Fig. a - Pseudo-colour infrared rendition of a sub-area of a Casi image (60 cm/pixel) of the Nahmint Lake species trial area in the central forest of Vancouver Island, British Columbia, Canada. The delineated areas (in white) correspond to stands judged relatively uniform by a forester. The training and testing areas used for the classification were delineated where species are known to be homogeneous. Their respective species and colours are: Douglas-fir (Pseudotsuga menziesii) in red, grand fir (Abies grandis) in green, amabilis fir (Abies amabilis) in blue, westerm redcedar (Thuja plicata) in orange, and western hemlock (Tsuga heterophylla) in yellow.

Fig. b - The individual tree crown (ITC) classification of Figure (a) and its computer generated forest stand outlines using the same colour scheme as Figure (a).

Tranfer of detailled forest information to a geographic information system (GIS)

The ITC approach provides detailled information about forest stand content by attaching new stand attributes that summarize the individual tree crown information. For each stand, ITCPCD produces and populates fields summarizing its area (by pixels and by hectares) the number of ITCs, the crown closure and the stem density of the stand. For each species (SP01, SP02, ...), its presence is summarized in terms of the number of ITCs (ITCsnn), its percentage of the total ITCs in the stand (PERnn), its percentage of crown closure (CCnn), its stem density (SDnn) and its average crown diameter (DIAnn).

If a digital canopy height model is available, average tree height information is also reported for the stand and for each species. All this information is easily transfered to geographic information systems.

Typical fields added by ITCPCD as forest stand attributes.
Area
(p)
Area
(ha)
ITCs Closure Density SP01 ITCs01 PER01 CC01 SD01 DIA01 SP02 ITCs02
344478 8.61 2329 59.2 270 49 1193 51.2 62.5 138 5.8 50 ...
394856 9.87 2858 57.3 289 50 1024 35.8 29 103 4.5 47 ...
291189 7.28 1562 48.4 214 50 376 24.1 18.4 51 4.7 47 ...
114189 2.85 797 56.4 279 50 478 60 54.9 167 4.9 49 ...
751854 18.8 5330 56.5 283 49 1241 23.3 24.7 66 5.2 50 ...
963858 24.1 6416 52 266 46 2087 32.5 38.3 86 5.4 49 ...
226425 5.66 1456 60.1 257 49 603 41.4 45.5 106 5.7 50 ...
290765 7.27 2060 56.2 283 49 605 29.4 29.8 83 5.1 50 ...
321607 8.04 2392 56.8 297 49 766 32 29.6 95 4.7 46 ...
155049 3.88 1116 56.6 287 49 511 45.8 43.7 131 4.9 46 ...
249622 6.24 1743 58.2 279 50 628 36 30.1 100 4.7 49 ...
648686 16.22 4386 58 270 50 2218 50.6 53.2 136 5.4 51 ...

Typical fields added by ITCPCD as forest stand attributes.


Project status

  • On-going