Why is it hard to produce new varieties of trees?

Producing new varieties of trees is challenging due to their long growth cycles, which can take years or even decades before maturity. Additionally, trees have complex genetics and reproductive systems, making it difficult to achieve desired traits through traditional breeding methods. Environmental factors also play a significant role, as trees must adapt to various climates and conditions, further complicating the development of new varieties. Lastly, the time and resources required for research, cultivation, and testing add to the difficulty of this process.