Left indexing wood radical — declares
棍 a wooden object. The vast majority of stick and club nouns carry
木:
杆 (pole),
棒 (cudgel),
枝 (branch),
桩 (stake). Without this radical, the right-side
昆 just means 'sibling' or 'insect swarm' — the wood radical is what specifies 'long wooden stick'.