An other tree cures rheumatism is willow, a bark pepares on March-April, on juice secretion, when she is faster cutting, as on a young at three y.old doing cuts as circle, and connect with lateral cut and remove piece.

As dry her in good ventilated room, as layer one formed, as in bark having glycoside salicine, as in entering in organism of infusion, from this glycoside secreting salicylic acid, as effects,like aspirin, and also in barks are having tannins, vitamins C, flavonoids acids, as bark cures cold, fever, rheumatism, arthritis.
 As still my grandma used an old method with willow bark, as one tea.sp. dried bark ads in two glasses for cold water, infused for 4 hours, filtered, drink on half glass for 4 times/day before meal, as sometimes added root of saponaria as one part willow bark of, and root of Saponaria, as two tea.sp. added in two glasses for hot water, till first with infusion of hibiscus, given for grandfather till two glasses/day before meal, or used spirit infusion of part chopped bark in ten part of vodka, infused for two weeks, used one tea.sp. in water after meal, as good works in arthritis, rheumatism. 

Willow bark does not had a side effects as not irritates stomach and not dilutes blood.