Measure twice, count once.

As a [mighty] land-owner, I've also had another look at land areas [prev+prev]. There were no hectares until the metre had been triangulated out and therefore defined in 1793. A square 100m x 100m has an area of 1 hectare. Obvs from the name, if you have The Greek, there are 100 ares [10m x 10m] to the hectare. Our modest house occupies about a ½ are, while Crowe's, the field downhill from it, is a bit over 1 hectare in size.

Acres, which are still what old buffers like me and most of my neighbours are comfortable with, are smaller and older than hectares. Like a lot of old measure [foot, anyone?], acres are "anthropic" human sized rather than planetary. One acre is [1 furlong x 1 chain] or reducing to the same units [40 rods x 4 rods]. As a square 1 acre very close to 70 yd x 70 yd. [rod pole or perch] is 16½ ft long which might indeed be a handy length for a fishing rod [fishing pole in US] . . . to catch perch Perca fluviatilis. Ho Ho, Bob, but perch is rather (etymologically) from Latin pertica which is cognate with pike: the long spear used in early modern armies. They say that an acre was a comfortable day behind the ox-drawn plough. Ploughing being a Winter (= short-day) activity. 

Other plough-related area measures include

• oxgang - area ploughable by one ox in one year = ca. 15 acres. Preferred in Danelaw [N&E England]
  
• virgate - area ploughable by two oxen in one year. Preferred in Mercia/Wessex [S&W England]
  
• carucate or ploughland - area requiring a full team of 8 oxen to plough in the year = 8 oxgangs = 4 virgates = 120 acres = 50 hectares.
  

To the metric / decimal generation "16½" seems peculiar until your redefine it as ¼ chain which is 22 yards [of 3 feet]. And there are 10 chains to the furlong. And to ring gratuitous changes, there are 8 furlongs to the mile. In olden dayes, when I was at school, 2 furlongs = 440 yd was a standard length for running, and furlongs are still used in horse-racing. The athletic standard is now 400m which is 0.5% shorter than 2 furlongs. Easy to train for both when Brits and USAians went to the Paris "Chariots of Fire" Olympics in 1924.

Heck, even the thought of running is exhausting: back to areas!  I was looking at an old mappe of So Wexford in Feb and noted that areas (of townlands, say) are given in Acres, Roods and Perches. In this context [and metrologists must still be chewing their beards about the confusing cross-over), the perch is a square with each side 1 [rod pole or perch] long. That area is as near as dammit to 25 sq.m. A rood is ¼ acre or 40 (sq) perches. In England, "rod" is preferred, Ireland leans towards "perch". Both countries like Poles: in England since WWII, in Ireland since the 01 May2004 EU expansion.