Why doesn't the text change when the intvalue changes?

The problem is that you only change the value once. To fix this, move line 5 to be inside the loop:

local wood = sp:WaitForChild("WoodValue")
local woodvalue = wood:WaitForChild("Value")

if wood and woodvalue then
    while true do
        woodvalue.Value = woodvalue.Value + 1
	wood.Text = woodvalue.Value
        wait(0.1)
    end
end

However, if this not the only place woodvalue gets updated, it would be better to use the Changed event, like this:

local wood = sp:WaitForChild("WoodValue")
local woodvalue = wood:WaitForChild("Value")

if wood and woodvalue then
	woodvalue.Changed:connect(function()
		wood.Text = woodvalue.Value
	end)
	while true do
		woodvalue.Value = woodvalue.Value + 1
		wait(0.1)
	end
end