As stated before, if the 12 by 12 fan leaf wasn't being useful, the plant would drop it. Surely, you have seen a plant that has dropped leaves that weren't being useful correct? If not, you can take my word for it because I have seen it plenty of times. Not just on weed but all types of plants.
for example, its like using your muscles... if you don't use them, they deteriorate. Our body even follows the same process as the plants do! Looking at this logically, it would make sense for the muscles to deteriorate because they aren't getting used. Same thing goes with plants. if the leaf isn't being used, they deteriorate and die off.
now.. as to your questions.. Which one is taking up more resources? you are looking at it the wrong way, its not which one is taking up most resources, its which one is producing more resources. Surely, you see the difference correct? We don't go around saying the bigger apple tree is taking up more resources do we? We don't go around saying " omg, those lower apple tree leaves must be cut, they aren't useful and aren't getting any sunlight.." do we?
but... if you don't like the fact that your plant is taking up more nutrients by having the "huge" leaf then that's a personal problem. Don't be mad at the plant for using the nutrients YOU gave it. you give it nutrients and you reward it by chopping off the huge fan leaf. Why not just make the solution simpler and give the plant less nutrients... oh wait.. I believe you get the idea now.
next question... How can you say that the energy and water used to support the 12 inch leaf is less in proportion to the 5" leaf and it's contribution to the plant?
I don't. What I do say is that the 12 inch leaf produces more nutrients because its a huge ass leaf. Surely, we can agree that if a plant grows a 12 inch leaf and somehow the leaf stays green throughout the life cycle, it HAS produced more energy than it has used. otherwise, the leaf would have deteriorated and died off, correct?
You say you remove all large fan leaves because they aren't getting light and the nutes and energy is being wasted. How do you come to this conclusion? What makes you believe those leaves aren't producing enough energy to sustain itself and not only itself but the plant as a whole?
