## 3 Results and Discussion
### Spatial Pattern and Trend Analysis of Post-Fire Stands Regrowth Index (SRI)  
An annual stands regrowth index (SRI) series was estimated from the vegetation response after the fire. Most of the burned pixels suggest that vegetation responses follow a positive trend, increasing their annual SRI responses in subsequent years (1988-2006) after this fire event (Figure 8). It is evident from the figure that substantial change occurred within this region from 1988 to 2006. There was a small annual increase in SRI values during the first five years following the fire. However, there was a more robust annual increase between years 10 and 19 in the subsequent period. This change in the rate was due to intensive salvage harvesting of standing dead logs in the first two years following the fire and then coniferous trees were planted to restore the timber volume of coniferous species because lumbering was the main forest industry in this region [36]. Figure 9 presents a significance image and degree of significance for the post-fire stands regrowth index (SRI) trend from the study area using the simple non-parametric Mann-Kendall test (single pixel-based analysis). The blue-green color shows the statistically significant positive trends. Most of the study area had significant increases in SRI, corroborating accounts of a general greening of the burned area during this period. A trend was considered statistically significant (at \(P\leq 0.05\)) when the Mann-Kendall (MK) statistics U was either  
Figure 7: The evolution of RRI calculated using NDVI difference between fire scars and the unburned control area for the growing season average (April to October) and June (the month immediately after the fire in 1987) time series. Zero on the time scale represents the burn year, _i.e._, relative year 0 is the year of the wildfire event. Relative year \(-1\) and \(+1\) corresponds to the year before and after the fire event, respectively. \(\geq 1.96\) or \(\leq-1.96\)[29, 30]. Therefore, the degree of significance of the post-fire stands regrowth index (SRI) trend using a non-parametric Mann-Kendall test can be divided into four categories: U \(<-1.96\), significant downward trend; \(-1.96\leq\) U \(<0\), downward trend, however not significant; \(0\leq\) U \(<\)1.96, upward trend, however not significant; and \(1.96\leq\) U, significant upward trend (Figure 9b). Table 4 demonstrates that all very high (VH) damage pixels had an upward trend; there was a significant upward trend (Mann-Kendal significance (U) \(\geq 1.96\)) for 18% of the pixels and a non-significant upward trend for 82% of the pixels. Our results agree well with the findings of similar researches conducted by [PERSON] and [PERSON] _et al._[17, 37]. They found that larch abundance increases due to increasing planting intensity and the degree of increased abundance among these planting intensity scenarios is different. The results also suggest that approximately 65% and 61% of the high (H) and medium (M) fire damage pixels, respectively, underwent a non-significant upward trend. However, for the slight (S) and low (L) damage classes, this number was very low because tree planting mainly occurred in the severely burned area (approximately equal to the Medium, High and Very High fire damage areas combined). The main species planted was _L. gmelini_, with a small area of _P. sylvestris_ var. Mongolia and Korean Spruce (_Picea koriaensis_). Therefore, the severely burned area exhibited a better recovery trend than the lightly burned regions, similar to the results of [PERSON] _et al._ (2010). By 1997, approximately 50% of the severely burned area had been referested, mostly in high accessibility areas and locations with good site conditions. In the moderately burned areas (30%-70% of trees dead), human promoted restoration was conducted with mechanical plows. However, in the lightly burned areas (less than 30% of trees dead), natural regeneration was permitted to occur [36].