Table 3 Fraction, number and mean size of large, medium-sized and small gaps in different observation years
From: Dynamics of gaps and large openings in a secondary forest of Northeast China over 50 years
Characteristic | Class | 1964 | 1976 | 1986 | 1994 | 2003 | 2014 |
|---|---|---|---|---|---|---|---|
Gap fraction (%) | Large gap | 0.3 | 1.3 | 1.8 | 0.7 | 0.5 | 0.6 |
Medium gap | 1.5 | 0.9 | 1.3 | 1.4 | 1.9 | 0.7 | |
Small gap | 2.0 | 1.9 | –a | – | 2.7 | 1.3 | |
Total | 3.8 | 4.1 | – | – | 5.1 | 2.6 | |
Gap number | Large gap | 33 | 81 | 164 | 59 | 50 | 35 |
Medium gap | 647 | 524 | 342 | 457 | 691 | 231 | |
Small gap | 4369 | 4012 | – | – | 4578 | 4257 | |
Total | 5049 | 4617 | – | – | 5319 | 4523 | |
Mean gap size /SD (m2) | Large gap | 1227/420 | 2167/514 | 1482/473 | 1601/443 | 1350/354 | 2314/505 |
Medium gap | 313/121 | 231/104 | 513/375 | 413/106 | 371/175 | 409/253 | |
Small gap | 62/51 | 64/45 | – | – | 80/57 | 41/27 | |
Total | 101/195 | 120/145 | – | – | 129/117 | 74/231 |