Cruising Approaches Area Based Methods Tree Based Methods
Area Based Methods Main Types Strip Cruise Fixed Plot Point Sampling Remote Sensing Varieties for specific applications Fixed Count Fixed Count Measure Fixed Plot with 3P subsample Point Count Measure Point Sampling with 3P subsample 3P Point Sampling
Tree Based Methods Sample Tree Method For stands too variable in density to plot cruise or where trees are not suitable for cruising by other methods Examples – partial cutting, small clearcuts, stratification by species or size class is desired 3P Small or irregular shaped harvest units Widely scattered trees Very large stands Used where a wide volume range occurs within a species group Measure as few trees as possible Cut tree marking Not used in this region
Strip Cruising Strips could be randomly allocated. Hard to stratify without bias.
Disadvantages of strip cruising: 1. Inaccurate estimation of strip width may lead to errors. 2. Difficult to maintain a straight strip centerline. 3. Brush and windfall are more of a hindrance in this system. 4. Spot-checking the cruise is difficult: strip centerline is rarely marked. Strip Cruising Area Based Methods
Remote Sensing Best for low value products Best for even-aged, single canopy and species stands (tree farms) Needs recent high resolution photos Pre-sampling needed to establish relationships i.e. volume versus canopy cover estimates Photos must be geo-referenced
Fixed Plot 1. Locate Plot Center 2. Temporarily mark plot center with wire flag or paint for instance 3. Plot size targets 4 to 8 trees per plot 4. Use same size plot throughout 5. Plot radius checked with hipchain Pacing is less accurate
Determination of “IN” Trees Plot center to tree center Horizontal Limiting Distance HLD = Plot Radius – (0.5 X DBH/12) Must be corrected for slope if steeper than 10%
Slope Correction Slope Limiting Distance SLD = HLD X SCF or HLD = SLD/SCF SCF means Slope Correction Factor
Slope Correction Fixed plot size (acre) = ¼ Plot radius = 58.9 feet Measured distance to tree face = 59.8 feet DBH = 12.6 inches or 1.05 feet DBH/2 =.525 feet Slope percent = 20 Slope correction factor = 1.02 Limiting Distance = In or Out = SLD = (58.9 - 0.525) X 1.02 = 58.375 X 1.02 = 59.5 Out by 0.3 feet
Problem Trees – Forked Trees if the boundary passes through the center of the tree at DBH, count as IN
Problem Trees – Leaning Trees if the boundary passes through the center of the tree at DBH, count as IN
Problem Trees – Broken or Down Trees locate breast height at 4 and 1/2 feet above the root collar as the tree lies on the ground. If this point lies on or inside the plot boundary, the tree is IN
Must be tallied as having no trees for correct expansion factor to apply to whole site. Null Plots
Field Aids Species Codes Tree Codes Location Codes Tree and Log Grading Rules Percentage Deduction Tables Standard upper limit Diameter Outside Bark (DOB) by species Limiting distance tables for point-sampling Stratification guides
Recording Equipment Compass and/or GPS Clinometer or laser to determine slope D-Tape 100 foot tape or hipchain Flagging and/or paint Prism or angle gauge for point cruising Hypsometer Pencil and paper or Data Recorder
Forms Date = 8/19/2013Size = 1/10 th acreForest Cover Type = Stand Size and Condition = Stand Age = Stocking or Density Class = Site Index =Slope = Soil Classification = Understory Vegetation =Treatments needed = Plot = 1 TreeSpeciesDBHForm ClassHeightGradeCrown ClassNotes 1RO14781.52 2SP168022 3YP18822.51 Plot = 2 Etc.
Electronic Data Recorders Pocket Dog Pocket Dog FS Cruiser FS Cruiser If your field data recorder has built in GPS – even better. Can include location in tally data for periodic rescaling, etc.