Complex sentence: The Alaska Range, a mountainous expanse running through the entire park, provides interesting ecosystems in Denali, because the fall line lies as low as, wooded areas are rare inside the park, except in the flatter western sections surrounding Wonder Lake.
Split into simpler sentences: The Alaska Range, a mountainous expanse running through the entire park, provides interesting ecosystems in Denali. Because the fall line lies as low as, wooded areas are rare inside the park, except in the flatter western sections surrounding Wonder Lake.