Short answers, pulled from the story.
A shrub is defined as a small to medium-sized perennial woody plant with persistent stems above ground that survive year after year. Unlike trees, most shrubs possess multiple stems with no main trunk below ground level.
Some shrub species last about five years in good conditions while others live beyond 70 years. On average they die after eight years.
Shrubland is the natural landscape dominated by various shrubs found across the globe including fynbos maquis shrub-steppe shrub swamp and moorland. The last decades have seen shrubification in the arctic with marked increase of shrublands due to increased temperature.
Dense foliage cover ranges from 70 to 100 percent creating closed-shrubs while mid-dense foliage cover spans 30 to 70 percent forming open-shrubs. Sparse foliage cover measures between 10 to 30 percent defining tall shrubland environments.
Some shrubs produce valuable compounds including Jojoba oil from Simmondsia chinensis and spices like cinnamon from Cinnamomum species. The list includes over one hundred genera ranging from Abelia to Ziziphus with varying commercial applications.