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Title 190-Forestry Inventory Methods Technical Note <br />Table 2: Example Stand -Level Diameter Distribution Table Using 2-Inch Size Classes Between <br />10 and 18 Inches DBH <br />Douglas -Fir Lodgepole Pine Western Larch <br />DBH TPA BA TPA BA TPA BA <br />10 12 7 6 3 12 7 <br />12 13 10 4 3 8 7 <br />14 16 16 0 0 0 0 <br />16 7 10 0 0 0 0 <br />18 0 0 0 0 0 0 <br />Totals 48 43 10 6 20 14 <br />• Tree Regeneration Sampling in Conjunction With Point Sampling <br />o To obtain a complete stand description, consider collecting nested fixed -radius plots <br />for trees in the seedling, sapling, or pole size at the same time as conducting point <br />sampling of the stand overstory. A fixed -radius plot with the same plot center as the <br />point sample can yield useful information for either a forest management plan or a <br />conservation practice job sheet. Plot size is dependent on tree density. <br />o Choose a plot size that will capture stocking without having to count more trees than <br />necessary; a cursory walk through the stand will help determine an appropriate plot <br />size. If tree density appears low enough that a 1/300th acre plot will often be empty, <br />where a 1/100th acre plot will capture regeneration, then utilize the larger plot. <br />Conversely, when surveying an extremely dense stand, the smaller plot is better to <br />avoid missing stems. As with the BA factor, keep the same plot size for the entire <br />stand to make expansion calculations easier. <br />o Calculating Regeneration TPA <br />Using the example tally sheet in figure 6, the fixed area plots are 1/100th acre in <br />size (11.8 feet). <br />There were 11 trees tallied in the 8-inch diameter class and smaller. So, <br />TPA = 11 counted trees x 100 / 3 = 366 trees per acre <br />o Again, a diameter distribution table is very useful to help target treatment options <br />(table 3). <br />Table 3: Example Stand -Level Conifer Regeneration Table Showing Number of Trees in <br />Seedling, Sapling, and Pole Size Classes <br />DBH Douglas -Fir Lodgepole Pine Western Larch Totals <br />0-1 167 0 0 167 <br />2-3 0 0 0 0 <br />4-5 0 0 0 0 <br />6-7 0 66 33 99 <br />8-9 0 100 0 100 <br />Totals 167 166 33 366 TPA <br />Note that in different geographic areas and forest types, size classes are defined differently, so <br />that some of the DBH classes shown in this table would be part of overstory tallies. <br />(Technical Note No. 190-FOR-01, Jul 2018) <br />11 <br />