By Hans Nicholas JongPhilip Jacobson LABAN NYARIT, Indonesia — Ipu Angit’s close relationship with the forest here in the interior of Borneo is evident as he identifies the plants and trees he uses to meet his daily needs, venturing deeper in despite the hot, humid weather and his advanced age. One moment he deftly fashions a makeshift umbrella out of palm leaves. The next he points out some young rattan stems, which he often prepares to eat by boiling to reduce the bitterness and then either cooking them with turmeric or eating them raw. Lately, however, Ipu has been clouded by anxiety: the r…