This manual has been written as a guide for the measurement of MARVL-based inventory plots in the native forests of State Forests of NSW. It is intended to supplement, not replace formal face-to-face training. The manual describes field procedures for measuring bound primary plots.
Keep in mind that a sample of the plots which you measure will be audited for accuracy of plot location, plot layout and tree measurement/description. State Forests is relying on you to provide information which is - as far as possible - accurate, precise and consistent. Don't take short-cuts with any aspects of plot measurement, take enough time to do the best job you can. Attention to detail is crucial because, like all sampling systems, a small error at the plot or tree level becomes a large error at the inventory level.
While attempting to give an explanation of correct procedures for most aspects of MARVL plot measurement this manual cannot be expected to cover all possible situations encountered in the field. If, having read the relevant part of this manual, you are still unsure about any aspect of plot measurement you should contact your Field Supervisor or Scott Arnold (066) 528900 or (066) 534810 (a.h.), radio call sign 1013.
2. MARVL INVENTORY EQUIPMENT CHECKLIST
Map of plot to be measured, with plot location information
Hip chain cotton (keep a good supply)
Wire pegs (keep a good supply)
Vertex Hypsometer (and spare batteries)
30 or 50 metre tape
Spray paint (keep a good supply)
Proformas (keep a good supply)
Pencil & eraser (including spare leads)
Spare folders for storing finished plot sheets
Set of field notes (you’re reading them now!)
3. LOCATING PLOT POINTS
The plot location information provided by your Field Supervisor describes how to locate a road-side take off point (T.O.P.) for each plot. Using a hip-chain (not the trip meter in the vehicle) locate the T.O.P. Mark the T.O.P., along with the plot number, on a tree or other easily visible spot. See Figure 1 below, which shows a T.O.P. marked on a tree.
Figure 1: Marking the T.O.P. for Plot 15.
From the plot location notes read off the bearing and distance to the plot you intend to measure. Check that you have all necessary equipment before leaving the vehicle. Use the hip-chain and compass to locate plot point.
If you are sure there is a more efficient traverse which could be used to locate the plot then that should be used and ALL details of how the plot was located (ie: how to locate the T.O.P. and the magnetic bearing and slope distance from the T.O.P. to the plot point) must be recorded in the “comments” section of the proforma.
The plot should be established exactly where the hip-chain and compass bearing take you. If the plot point is in some way "different" to the general area, feel free to make note of this in the comments section of the proforma. THE PLOT SHOULD NOT BE MOVED FROM THIS SPOT UNLESS YOU ARE SURE YOU ARE IN THE WRONG PLACE. (Note: you can make an allowance of about 5% of the traverse distance for survey error during the course of locating the plot point.)
3.1 Marking the Plot Point
In situations where the plot point falls on rock, or a log, or any other immovable object you should mark the centre of the plot with a cross of paint on the log or rock. In all other cases a wire peg with flagging tape should be used to mark the plot point. The plot number should be painted on the tree nearest to the plot point. At the end of the measurement work the plot point should be repainted to allow audit crews to easily find the actual plot point.
The plots in the Strategic Inventories are circular bound plots. The size of the plot will be shown on the plot location information given to you by your Field Supervisor. The plot point mark on the ground is the centre of the plot and the horizontal radius of the plot is 12.62 metres for a 0.05 hectare plot and 17.84 metres for a 0.1 hectare plot.
4.2 Plot Slope
The slope of the plot is measured by standing at the plot point and measuring the slop of the ground in the steepest direction of the plot and the slope in the opposite direction. The two readings are averaged to get plot slope.
In order to ensure that all plots occupy the correct area the slope of the ground needs to be taken into account. This is only critical for trees which are close to the plot boundary. The procedure for allowing for slope is done on an individual tree basis. In other words, each “close tree” (ie within 0.5 metres of the plot radius) must be checked for the slope and the slope distance from the plot point to the middle of the side of the tree at 1.3 metres.
For “close trees” the slope angle to the tree is measured by taking a clino reading from the plot point to the tree (at eye level). The next thing to be done is measure the slope distance from the plot point to the middle of the side of the tree at 1.3 metres. To do this, one person should hold the end of the 30 or 50 metre tape 1.3 metres directly above the plot point marked on the ground while another person holds the other end of the tape at the middle of the side of the tree at 1.3 metres. At all times the tape should be held tight, straight (no bending around trees, branches, etc) and parallel to the ground.
The slope angle and slope distance are looked up in the Slope Correction Table in Appendix 1 on page 19. If the slope distance to the tree is less than, or equal to, the distance shown in the table then the tree is in, otherwise the tree is out. Trees which have been checked but are out should have a cross painted on the tree facing the plot point.
4.4 Marking the Plot Boundary
Having located (and marked) the plot point, the next thing to do is set out the plot boundary. This is best done using the Vertex§ to lay out a circle surrounding the plot point.
One person should hold the transponder 1.3 metres directly above the plot point while another person sweeps around the plot perimeter measuring the distance of all trees which appear close to the plot radius. The hypsometer should be held at the middle of the side of the tree at 1.3 metres when measuring distances. While most trees will be clearly in or out, any which are within 0.5 metres of the plot radius will need to be checked using the slope correction method described in Section 4.2.
Please take care when checking “close” trees because one tree in or out of a plot can make a difference of several hundred cubic metres!!
Which Trees Are In? Once the boundary of the plot has been determined, all trees with a diameter at breast height (1.3 metres) greater than 100 millimetres are recorded. No palms or ferns should be included. No trees which have a DBHob less than 100 millimetres are included.
All “in” trees should have the tree number and DBHob mark painted on them. The tree number is painted on the side of the tree facing the plot point and the DBHob mark is painted on the side of the tree where the 1.3 metres was measured.
For details on measuring and assessing the “in” trees, refer to Section 5 “Measuring Trees”, on page 9 and Section 6 “Assessing Trees” on page 12
There is a list of pieces of information which needs to be recorded for each plot. The following sections contain a description of what each bit of information (or “attribute”) means and how it is recorded.
In the “Inventory” field of the Plot Header record the Inventory Identifier for the plot you are measuring. The Inventory ID will be provided to you with all the plot location information by your Field Supervisor. The format of the Inventory ID is a two digit number with no leading zeros (eg: 1).
4.5.2 Management Area
In the “MA” field of the Plot Header record the Management Area Identifier for the plot you are measuring. The MA ID will be provided to you with all the plot location information by your Field Supervisor. The format of the MA ID is a two digit number with no leading zeros (eg: 12).
4.5.3 State Forest Name
In the “SF” name field of the Plot Header record the name of the State Forest which contains the plot you are measuring.
In the “Cpt. No.” field of the Plot Header record the compartment number of the plot you are measuring.
In the “Aspect” field of the Plot Header record the record the magnetic bearing of the direction of maximum slope as a 1-digit code. Codes are:
1 0° - 45°
2 45° - 90°
3 90° - 135°
4 135° - 180°
5 180° - 225°
6 225° - 270°
7 270° - 315°
8 315° - 360°
0 Flat - no appreciable aspect
4.5.6 Plot Number
In the “Plot No” field of the Plot Header record the record the five digit plot number shown on the plot location information page, with leading zeros. Eg: 01023 for Plot 1023, or 21008 for Plot 21008.
In the “Stratum” field of the Plot Header record the Stratum ID for the plot you are measuring. The Stratum ID will be provided to you with all the plot location information by your Field Supervisor. The format of the Stratum ID is a two digit number with leading zeros (eg: 02).
4.5.8 Plot Size
In the “Plot Size” field of the Plot Header record the size of the plot, in hectares with a leading zero for the decimal place. (eg: 0.05 for a 0.05 hectare plot, or 0.1 for 0.1 hectare plot.) The Plot Size will be provided to you with all the plot location information by your Field Supervisor.
In the “Slope” field of the Plot Header record the slope of the plot you are measuring. For details on how to measure plot slope refer to Section 4.2 on page 4.
4.5.10 Filter Strip Distance
In the “Filter Strip Distance” field of the Plot Header record the distance from the plot point to the bank of the nearest drainage line requiring a filter strip. If the distance to the nearest drainage line requiring a filter strip is greater than 50 metres, then leave this field blank.
If a definite, unmapped filter strip is found within 50 metres then the location of the drainage line should be added to the map.
In the “Date” field of the Plot Header record the date you started measuring the plot. Record the date using dd/mm/yy format (eg: 24/11/97).
Record the “Crew Number” for your crew. Your field supervisor will be able to provide you with this number if you are not sure.
4.5.13 Site Height
In the “Site Height” field of the Plot Header record the Site Height of the plot you are measuring. For more details on measuring Site Height refer to Section 5.2 on page 10.
4.5.14 Tree Number
In the “Tree No.” column record the tree number (starting from 1) for each tree in the plot you are measuring. Because some trees will take up more than one line on the proforma it is easier to record the tree number as the trees are being measured and assessed, rather than listing all the tree numbers one after the other at the start of tree measuring.
In the “Spp Code” column record the standard three letter code for the species of tree you are measuring. A list of standard species codes form Appendix 3 on page 22.
Note that the MARVL computer system can only recognise the standard codes shown in Appendix 3, so if you can’t find a code which could apply to the tree you are measuring (note: there are several “general” codes for such occasions) and you “invent” a new code you must tell your Field Supervisor.
4.5.16 Diameter (DBHob)
In the “DBH (mm)” column record the diameter of the tree you are measuring in millimetres. For more information on measuring diameters refer to Section 5.1 on page 9.
4.5.17 MARVL Tree Description
In the “MARVL Tree Description” column record the description of the tree you are measuring. For more information on MARVL tree descriptions refer to Sections 6.5 on page 13 and 6.6 on page 15.
4.5.18 Crown Condition
In the column “Crown Condition” record the Crown Condition of the tree you are measuring. For more information on Crown Condition refer to Section 6.1 on page 12.
In the column “Dominance” record the Dominance of the tree you are measuring. For more information on Dominance refer to Section 6.2 on page 12.
4.5.20 Hollow Status
In the column “Hollow Status” record the Hollow Status of the tree you are measuring. For more information on Hollow Status refer to Section 6.3 on page 12.
4.5.21 Logging Impediment
In the column “Logging Imped” record the Logging Impediment of the tree you are measuring. For more information on Logging Impediment refer to Section 6.4 on page 12.