Toward improving reforestation of Brazilian pine (Araucaria angustifolia), two contrasting sapling sizes in either full sun or in the shade of a mixed plantation and the effect of opening the canopy were evaluated for survival, growth, gas exchange, photosynthetic pigments, and leaf anatomy 18 months after being planted. At 23 months after planting, a partial opening was made in the canopy in the mixed plantation, then the saplings were evaluated again after 2 months for the same morphophysiological traits. After 18 months, saplings planted in the full sun had higher survival, growth, pigments, and photosynthesis compared to the shaded saplings. Large saplings had higher survival and growth compared to the small ones. Shaded leaves were thinner and little differentiation of palisade parenchyma and hypodermis. After opening of the canopy, photosynthetically active radiation was 10 times higher, and the saplings quickly grew in height due to increased photosynthesis. Thus, although the species can tolerate shade, growth in the shade is limited. We recommend that for reforestation purposes of Brazilian pine, large saplings should be selected and planted in the open for better development.

改善巴西松 ( Araucaria angustifolia) 的重新造林)，在种植 18 个月后，评估了两种不同大小的树苗在充足的阳光下或在混合种植园的阴凉处以及打开树冠的效果的存活、生长、气体交换、光合色素和叶片解剖结构。在种植后 23 个月时，在混合种植园的树冠中进行部分开口，然后在 2 个月后再次评估树苗的相同形态生理性状。18 个月后，与遮荫树苗相比，在充足阳光下种植的树苗具有更高的存活率、生长、色素和光合作用。与小树苗相比，大树苗具有更高的存活率和生长率。阴影叶较薄，栅栏薄壁组织和皮下组织很少分化。打开树冠后，光合有效辐射高出 10 倍，由于光合作用增加，树苗的高度迅速增长。因此，虽然该物种可以忍受阴凉，但在阴凉处生长是有限的。我们建议巴西松的再造林应选择大树苗并在露天种植以更好地发展。