Fence type Main materials Cost per 100 m ($) Expected lifespan (years) Barbed wire Steel wire, timber posts 250 15 Mesh wire Woven steel mesh, timber posts ...

(a) Fence type with lowest initial cost [1]

From the table, the live fence / hedge has the lowest initial cost at $60 per 100 metres [1]. This is because the main materials are living shrubs and small trees, which are far cheaper than manufactured wire, mesh or quarried stone.

(b) What is a live fence? [2]

A live fence is a barrier made from living plants such as shrubs or closely planted small trees [1]. As the plants grow, they form a continuous, dense hedge that prevents livestock from passing through [1]. Unlike wire or stone fences, a live fence is self-renewing provided it is maintained.

(c) Why mesh wire is more suitable than barbed wire for goats [2]

Mesh wire fencing has much smaller gaps between the wires compared to barbed wire [1]. Goats are agile and inquisitive animals that will squeeze through wide gaps or push their heads between strands; the tight weave of mesh wire physically prevents this, whereas the widely spaced horizontal strands of barbed wire leave openings large enough for goats to get through [1].

(d) One advantage of a stone wall in a windy, exposed area [1]

A stone wall provides a solid windbreak that gives shelter to livestock on the lee side [1]. Unlike wire fencing, wind passes through wire strands without being blocked, offering no protection. A stone wall also does not rust, corrode, or require tension maintenance and has a very long lifespan (50+ years as shown in the table).

(e) One disadvantage of a live fence [1]

Any one of the following:

• Takes several years to grow to an effective stock-proof height [1].
• Requires regular trimming and maintenance to remain dense and stock-proof [1].
• May harbour pests or diseases that affect nearby crops [1].
• Takes up more land area than a wire or stone fence [1].