Extensions of forest-transition theory to the tropics often depict sustained expansions of planted tree cover and corresponding long-term net gains in total tree cover. To explore the patterns and implications of continued tropical planted tree-cover expansion, we profiled sequences of tree-cover change over 1990–2010 according to Landsat imagery for recently observed (ca. 2014) planted tree-cover areas in 11 tropical countries. Alternative patterns of change emerged from these analyses. Termed the ‘reforestation treadmill’ and ‘forest transformation’ narratives, planted tree-cover change featured relatively ephemeral planted covers, modest net gains, and similar tree-cover change dynamics compared to nearby agricultural-forest mosaics. Planted areas were characterised not by unambiguous reforestation but rather combinations of tree-cover losses and gains, with losses typically being more prominent. Contemporary gains and losses during 5–10-year periods regularly distinguished planted areas from non-planted areas, with losses being 1.5–2.3 times more common than gains. Planted areas were only moderately distinguishable from non-planted areas overall with respect to tree-cover change dynamics. Relationships between tree-cover change and the export orientations of planted tree/tree-crop commodities were also examined. Greater export orientations did not significantly associate with tree-cover loss or larger planted patches, with partial exceptions for Southeast Asia. Regional disparities in planted tree-cover dynamics were apparent. In Southeast Asia, dominated by Indonesia, tree-cover declines in planted areas since 1990 were relatively pronounced (20% of planted areas), particularly with respect to progressive transitions from tree cover to cleared lands. Planted areas there were generally indistinguishable from nearby non-planted areas with respect to historical tree-cover change dynamics. In contrast, in South America, dominated by Brazil, tree-cover increases in planted areas since 1990 were more appreciable (at least 14% of planted areas), with most being progressive, stable, ‘net’ increases (10% of planted areas) and the remainder being dynamic increases entailing short-term losses since 1990 (4% of planted areas). Total tree-cover increases within South American planted areas were equal to or greater than total decreases since 1990. These patterns suggest a forest-transformation narrative in which major planted-area expansion occurs alongside minor net tree-cover change. This narrative appears particularly well suited to Southeast Asia, where planted areas are extensive and expansive but where net tree cover gains are tenuous, reflecting political-economic shifts in forest management and the devaluation of extensive, degraded natural forests.

森林过渡理论向热带地区的扩展通常描述了人工林覆盖率的持续增长，以及总的树木覆盖率的相应的长期净收益。为了探索热带树木种植持续增长的模式和意义，我们根据Landsat影像对11个热带国家最近（2014年左右）种植的树木覆盖区域进行了分析，根据1990-2010年的树木覆盖变化序列。从这些分析中得出了变化的替代模式。被称为“重新造林的跑步机”和“森林转型”的叙述，与附近的农林马赛克相比，种植的树木覆盖变化具有相对短暂的种植覆盖，适度的净收益以及类似的树木覆盖变化动态。种植区的特点不是明确的重新造林，而是树木覆盖的损失和收益的结合，损失通常更为突出。在5-10年间，当代损益通常会将种植区与非种植区区分开来，损失是获得收益的1.5-2.3倍。就树木覆盖变化的动态而言，种植区域与非种植区域总体上只有中等程度的区别。还研究了树木覆盖率变化与种植的树木/树木作物商品的出口方向之间的关系。更大的出口导向与树木覆盖率的损失或更大的种植斑块没有显着联系，东南亚除外。植树覆盖动态的区域差异是显而易见的。在以印尼为主的东南亚地区，自1990年以来，种植面积的树木覆盖率下降相对明显（占种植面积的20％），特别是在从树木覆盖到砍伐土地的逐步过渡方面。就历史树木覆盖变化动态而言，那里的种植区通常与附近的非种植区没有区别。相比之下，在以巴西为主的南美地区，自1990年以来种植面积的树木覆盖率增长更为可观（至少占种植面积的14％），其中多数是渐进的，稳定的“净”增长（占种植面积的10％） ），其余则是动态增长，这导致1990年以来出现短期损失（占播种面积的4％）。自1990年以来，南美种植区的树木覆盖总增加量等于或大于总减少量。这些模式暗示了一种森林转型的叙事，其中主要的种植区扩张与次要的净树覆盖变化同时发生。这种说法似乎特别适合于东南亚，该地区的种植面积广泛而广阔，但树木的净覆盖率却微不足道，这反映了森林管理方面的政治经济变化以及广泛退化的天然林的贬值。