Лиственный.

А вот цитаты на английском. Для сравнения.

"Beyond it were slopes covered with sombre trees like dark clouds. but all about them lay a tumbled heathland, grown with ling and broom and cornel, and other shrubs that they did not know. Here and there they saw knots of tall pine-trees".

"Heather and trees and bracken scrambled down and overhung the banks, or sprawled out over the surface".

"All about them were small woods of resinous trees, fir and cedar and cypress, and other kinds unknown in the Shire, with wide glades among them; and everywhere there was a wealth of sweet-smelling herbs and shrubs.<...>Here Spring was already busy about them: fronds pierced moss and mould, larches were green-fingered, small flowers were opening in the turf, birds were singing".

"Many great trees grew there, planted long ago, falling into untended age amid a riot of careless descendants; and groves and thickets there were of tamarisk and pungent terebinth, of olive and of bay; and there were junipers and myrtles; and thymes that grew in bushes, or with their woody creeping stems mantled in deep tapestries the hidden stones; sages of many kinds putting forth blue flowers, or red, or pale green; and marjorams and new-sprouting parsleys, and many herbs of forms and scents beyond the garden-lore of Sam. The grots and rocky walls were already starred with saxifrages and stonecrops. Primeroles and anemones were awake in the filbert-brakes; and asphodel and many lily-flowers nodded their half-opened heads in the grass: deep green grass beside the pools, where falling streams halted in cool hollows on their journey down to Anduin <...>Presently it brought them to a small clear lake in a shallow dell: it lay in the broken ruins of an ancient stone basin, the carven rim of which was almost wholly covered with mosses and rose-brambles; iris-swords stood in ranks about it, and water-lily leaves floated on its dark gently-rippling surface; but it was deep and fresh, and spilled ever softly out over a stony lip at the far end".

"A little way back above the lake they found a deep brown bed of last year's fern. Beyond it was a thicket of dark-leaved bay-trees climbing up a steep bank that was crowned with old cedars".

"As the third stage of their day's march drew on and afternoon waned, the forest opened out, and the trees became larger and more scattered. Great ilexes of huge girth stood dark and solemn in wide glades with here and there among them hoary ash-trees. and giant oaks just putting out their brown-green buds. About them lay long launds of green grass dappled with celandine and anemones, white and blue, now folded for sleep; and there were acres populous with the leaves of woodland hyacinths: already their sleek bell-stems were thrusting through the mould".

Вообще растительность какая-то средиземноморская. Оливы, лавры. И кедры, по-моему, не те, что "сосна кедровая" и растут в Сибири, а те, что у нас называются ливанскими, что ли.
Что, в общем-то, логично. Море недалеко, климат тёплый.