PRFgrowth is the implementation of growth functions developed from
repeat airborne laser scanning acquisitions at the Petawawa Research
Forest.
Currently, two functions are available, Hgrowth returns the estimate
of the final top height and HGSIndex calculates the height growth rate
index at a reference height for a given period.
HGSIndex provides a comprehensive indicator of site quality based on
age-independent height growth models Hgrowth for various forest types
in the Great Lakes–St. Lawrence Forest region in southern Ontario,
Canada.
| Forest | Code | Description |
|---|---|---|
| White Spruce | SW | Planted white spruce stands with various initial densities and subsequent management activities, in some cases with an understory of poplar and hardwoods |
| Jack Pine | PJ | Naturally occurring and planted jack pine stands at various densities |
| White Pine | PW | Stands dominated by white pine covering a range of plantations and managed and unmanaged natural stands in a mixture of red pine and an understory of other tree species |
| Red Pine | PR | Natural and managed stands dominated by red pine |
| Mixedwood conifer | MXC | Mixed species conifer stands with a range of species proportions dominated by black spruce, white spruce and balsam fir |
| Mixedwood hardwood | MXH | Hardwood mixed species stands with various species proportions of red maple, poplar and white spruce, with a lesser component of yellow birch, oak |
| Intolerant hardwood | INT | Natural stands dominated by poplar (large-tooth and trembling aspen leading) and often mixed with other hardwoods and conifers |
| Tolerant hardwood | HD | Stands covering a range of structures and associated species (sugar maple, yellow birch, with a lesser component of red maple, beech, oak, hemlock, spruce and balsam fir) |
| Red Oak | OR | Natural immature and mature oak dominant and oak-pine mixed stands, often with an understory of poplar and hardwoods |
The under-development version of PRFgrowth can be installed like so:
#install.packages("devtools")
#devtools::install_github("jgriofrio/PRFgrowth")
library(PRFgrowth)Hgrowth estimates the final top height based on the initial height H0
and period length Dt. The function allows for predicting height
increments for different period lengths and obtaining instantaneous
growth estimates based on height as a state variable instead of age.
Hmodel(H0=10, ForT='PJ',Dt=7)
#> [1] 13.41243HGSIndex estimates the height growth index based on the height
increment (H1-H0)/Dt and at height reference Hr. H1 and H0 are
the top height at the final and beginning of the growth period,Dt is the
period length. Hr is an arbitrary and user-defined value analogous to the
reference age for height-age site index models. The selected reference
height is a balance between the size at which the most dominant trees
would have surpassed the initial period of intense competition following
their establishment and a height that can be conveniently measured.
HGSIndex(H0=10, H1=15, ForT='PJ',Hr=15,Dt=7)
#> [1] 0.5363001| Author | Affiliation |
|---|---|
| Jose Riofrio | University of British Columbia |
| Joanne C. White | Canadian Forest Service |
| Piotr Tompalski | Canadian Forest Service |
| Nicholas Coops | University of British Columbia |
Riofrío, J., White, J.C., Tompalski, P., Coops, N.C., Wulder, M.A., 2022. Harmonizing multi-temporal airborne laser scanning point clouds to derive periodic annual height increments in temperate mixedwood forests. Can. J. For. Res. 52, 1334–1352.
Riofrío, J., White, J.C., Tompalski, P., Coops, N.C., Wulder, M.A., 2023. Modelling height growth of temperate mixedwood forests using an age-independent approach and multi-temporal airborne laser scanning data. For. Eco. Manag. 543.
Ongoing development of PRFgrowth was supported with funds from the Canadian Wood Fibre Centre (CWFC) of the Canadian Forest Service.