ACROSS
2. A tree that has long, thin needles instead of leaves and that stays green throughout the year → PINE

3. A type of tree that grows in northern parts of the world and that produces acorns → OAK
 
4. A tall plant with hard hollow stems that are used for building and to make furniture, tools, etc. → BAMBOO

6. A tree of the family Arecaceae usually characterised by having a single stem or trunk, directly from which sprout several leaves or fronds giving a shape like an outstretched hand. → PALMTREE

7. A type of tree that produces large, sweet nuts that can be eaten. The female flowers develop into spiny cupules containing 2–5 brownish nuts.→ CHESTNUT


DOWN
1. An ornamental or shade tree and has fan-shaped leaves and foul-smelling yellowish fleshy seed coats → GINKGO

5. A tree or shrub with lobed leaves, winged fruits, and colourful autumn foliage, grown as an ornamental or for its timber or syrupy sap →
  MAPLE