RAINFOR GEM Intensive Plots Manual (pdf) - University of Oxford

all of the large, marked wood pieces which remain on the transect. The values of both the mass of the smallpieces in bags, and diameter of the individual large pieces should be stored in a datasheet.Decomposition Level (following Harmon et al.1995 80 as in §3.4)1 (little decay: bark cover extensive and leavesand fine twigs present)2 (logs and snags relatively undecayed but withno leaves and few fine twigs and bark has startedto fall off)3 (logs and snags with no bark and only a fewbranch stubs remaining; although in this class thesapwood is decaying, the heartwood is relativelyundecayed, and branch stubs do not move whenpushed or pulled)4 (no branches or bark cover; outer portions ofthe wood are often casehardened and the innerwood is decomposing)5 (logs are elliptical in cross-section (indicativeof advanced decay) and often the wood isscattered across the soil surfac)LeavespresentFinetwigspresentIntactbarkFirmwoodSoftwoodyes yes yes yes no nono no yes yes no nono no no yes no nono no no no yes nono no no no no yesVerysoftwoodTo derive estimates of coarse woody debris dry weight, the additional weight of the canvas bags and the waterwithin the wood (for the small wood pieces) and wood density (for the larger pieces) must be subtracted.Therefore, back at the lab weigh (1) the canvas bags (should be approx. 50 g), and (2) each individual woodpiece saved (5 decomposition categories, 30 per category, 5 * 30 = 150 total) before and after drying at around80°C to constant mass. Then place each wood piece into a graduated water flask half full with water and record(3) the volume of water displaced (remember 1 ml = 1 cm 3 ). Pieces from decomposition categories 4 and 5should be wrapped in clingfilm before immersion to avoid saturation of airspaces within the wood (whichwould then lead to an underestimation of wood volume). These measurements should also be noted in the samedatasheet, as wood mass and diameter.Wood density may be calculated as wood dry mass divided by volume. The volume of the larger woodpieces which could not be removed from the transects may be estimated from the equation for a cylinder:3.1416 * (diameter/2) 2 * length. Mean wood density for the appropriate decomposition category, multiplied bythe piece volume, gives an estimate of dry mass of each large wood piece. Total coarse litter mass per unitground area may be calculated as the sum of all the weighed bags (minus the weight of water in the wood andthe bags themselves) and the larger wood pieces which could not be removed from the transects.Diameter and length measurements of each wood piece may be used to calculate surface area with: (2 *3.1416 * ((diameter/2) 2 )) + (2 * 3.1416 * (diameter/2) * length). The sum of the surface areas of the piecesencountered gives an estimate of coarse litter surface area per unit ground area.Coarse litter should be collected every two months from within all four transects. If there is a reasonably highproduction of dead branches, it is most efficient to collect the representative wood pieces required for §3.4 aspart of the survey described here.80 n.b. these categories differ slightly from those in Baker & Chao (2011).65