1) It has a general meaning of ‘rubbish’ but in wood management the reference was to fallen branches or what was left over when the tanners and charcoal burners had used what they wanted, usually branches but sometimes whole trees. It could clearly be used in fencing.
c.1270 Habeant ramillum ad claudendas sepes circa terram, Whitby
1307-8 De ramill quercuum, alnetis et de alio bosco prostrato per ventum … et venditis, Bolton Priory
1373-4 Et in v plaustris cariantibus ramallum de Benetbank, Leeds
c.1495 50 plaustrata de subbosco [underwood] vocato ramyll, Pickering
1549 bushes, thornes and other ramell … for fuel, Stockeld
1711 Hessell, Birch and such like ramill, Hunsworth.