What does it mean that the five elements belong to wood or fire?

It should mean that the nature of some industries conforms to the attributes of wood or fire in the five elements, such as:

Five elements belong to fire industry

Flammable goods, edible oil, hot drinks and cooked food, maintenance technology, computer appliances, electronic fireworks, optical glasses, advertising videos, decoration and makeup, lighting stoves, toys and beauty.

Five elements belong to wood industry.

Wood products, wood, furniture, decoration, flowers, trees, seedlings, potted plants, bamboo, music, tea, paper machines, books, literature and art, cultural and educational bookstores, stationery stores, education, cultural undertakings, writers, teachers, publishing, religious industries, spices and worship supplies, cloth, justice, military and police, politics, public services, planting, stationery stores. ...

Scholars in literature, literature and art, stationery stores, cultural undertakings, literati, writers, writers, writing articles, teachers, principals, educational products, bookstores, publishing houses, officialdom, judicial circles, public security and police circles, officialdom, politics, new creation circles, special animal and plant growth circles, and plant planting experiments. Wood, wood products, wood products, furniture, decorative wood products, paper industry, bamboo industry, planting industry, flower industry, seedling industry, qingguoshan industry, grass industry, medicine industry [opening pharmacies or pharmacists] and medical industry. The fields of cultivating talents, buying and selling cloth, selling articles for worship or spices, religious applications, religious undertakings or selling vegetarianism all belong to wood industry.