treeVolCalculator: Calculate volume for trees
In bcgov/BCForestGroundSample: BC forest ground sample compilation

Description Usage Arguments Value Author(s)

This function is to calculate tree volume using taper equations on a basis of 10 cm slice. As default, the function is to calculate whole tree volume (VOL_WSV), total merchantable volume (VOL_BELOW_UTOP) and non-merchantable volume (VOL_ABOVE_UTOP) based on FIZorBEC, species, height, DBH using Kozak BEC taper equations. The function also handles broken top trees by specifying BTOPEstimateType, BTOPHeight and BTOPDIB. Accordingly, VOL_BELOW_BTOP and VOL_ABOVE_BTOP are produced. Lastly, the function derives volume (denoted as LOG_V_X), merchantable volume (denoted as LOG_VM_X) and top inside bark diameter (denoted as LOG_D_X) for each log when the logLengthMatrix is provided. For all the scenarioes, stump height (HT_STUMP), inside bark diameter at stump height (DIB_STUMP), breast height (HT_BH), inside bark diameter at breast height (DIB_BH) are generated.

treeVolCalculator(FIZorBEC, species, height, DBH,
  taperEquationForm = "KBEC", volMultiplier = 1, stumpHeight = 0.3,
  breastHeight = 1.3, UTOPDIB = 10, BTOPEstimateType = NA,
  BTOPHeight = NA, BTOPDIB = NA, logLengthMatrix = data.table(Log1_L
  = numeric()), logMinLength = 3)

`FIZorBEC`	character, Specifies which FIZ or BEC (depends on taperEquation) zones the tree located in BC.
`species`	character, Tree species, must be BC species code.
`height`	numeric, Total tree height in meter.
`DBH`	numeric, DBH of the tree in cm.
`taperEquationForm`	character, Specifies which taper equaiton will be used, currently support KFIZ3 or KBEC. See function `DIB_ICalculator` for details. Default is KBEC, if missing.
`volMultiplier`	numeric, Volume adjustment multiplier. If missing, 1 (no adjustment) is used.
`stumpHeight`	numeric, Defines stump height. If missing, 0.3 m is used.
`breastHeight`	numeric, Defines the breast height. If missing, 1.3 m is used.
`UTOPDIB`	numeric, Merchantable inside-bark diameter. If missing, UTOP is 10.
`BTOPEstimateType`	integer, Must among NA, 1, 2, 3. Defines whether a tree has broken top and which field observation (height at broken or DIB at broken ) is used to define broken point. NA means that tree is not broken top. 1 and 3 means diameter at broken top is not available, height at broken top is used to define broken point. 2 means diameter at broken top is available and is used to define broken point. Default is NA: tree does not have broken top.
`BTOPHeight`	numeric, Height at broken top.
`BTOPDIB`	numeric, Diameter inside bark at height of broken top.
`logLengthMatrix`	data.table, Log length matrix. If missing, there is no log-level volume returned.
`logMinLength`	numeric, Minimum log length. This argument is activated when logLengthMatrix is provided.