| Answer | Crossword Clue |
|---|---|
| ALDERS | Their bark is used in tanning. |
| ALDER | Its bark is used in dyes and tanning |
| BIRCH | Tree whose bark is used in writing paper |
| IONS | Their exchange is used in water softening |
| TAMARINDS | Their fruit is used in Worcestershire sauce |
| SLIPPERYELM | Its bark is used as an herbal supplement |
