Ozzy's Forest Chop Grid

I didn't see this information anywhere else, so I'm starting a new thread for it.

The amount of hammers you earn from chopping a forest decrease the further the forest square is from your city. Cultural borders have no effect, its based on the city square. The following grid shows the number of hammers for each forest square positioned around your capitol. 8 squares out is the maximum distance you can still get hammers from a forest chop.

Production modifiers apply to forest chop values. For instance a city with a Heroic Epic will earn twice as many hammers from a forest chop when building a unit then otherwise. Leader trait bonuses modify the values as well. Whether you are playing epic, normal, or quick affects the values, and charts for each speed are posted below.

Base terrain does not change the forest value. Thus forest on a grassland, hill, plain, etc all gives the same number of hammers depending on distance.

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Epic Length Chart

Thanks, much appreciated. It's mind boggling that someone didn't get this out sooner.

This is pretty easy to convert to a formula:

production bonus = FLOOR((speed factor) * (distance factor))

speed factor = 2/3 quick, 1 normal, 3/2 epic

distance factor = 30 - 5 * MAX(FLOOR(distance-3), 0)

Where distance is defined in the usual Firaxis sense, MAX(x,y)+1/2*MIN(x,y) or 3/4*(x+y)+1/4*ABS(x-y).

By the way, forest chop values also seem to be affected by the same (somewhat bogus) "current build overflow adjustments" as other production is.

It appears that the best squares to chop are 3 tiles from your city if your trying to keep trees in the radius for healthiness. You get the full chop value for the trees with no additional unhealthiness. It is also important that you get the most bang for your buck when chopping. That is, chop wonders when industrious, units if city has heroic epic. etc.

CiverDan said:

It is also important that you get the most bang for your buck when chopping. That is, chop wonders when industrious, units if city has heroic epic. etc.

Click to expand...

No, it doesn't matter, because you get the same bonuses for your regular production and the chop production.

E.g., suppose you're building a wonder that costs 250 hammers, and you have a 50% industrious bonus and 100% resource bonus. Then you build a building that costs 80 hammers, with no bonus. If you chop 2 forests for the wonder, you get 2*30*2.5 = 150 toward the wonder, so you need to use 40 hammers (times 2.5 multiplier) to finish the wonder, and then 80 hammers to build the building, for 120 total. Alternatively, if you chop the 2 forests for the building, then you get 60 credit and need to put in another 20, and the wonder costs you 100 (times 2.5 multiplier), which is the same 120 total. So you get the same result whether you chop for one or the other.

Edit: This bug was fixed in patch 1.52!

Production bonuses can be abused to increase the value of forests. If you have 1 shield left on your +150% wonder and chop 4 forests, that's a 299 shield overrun that you can apply to any item you want.

DaveMcW said:

Forests can be abused to extend the production bonus. If you have 1 shield left on your +150% wonder and chop 4 forests, that's a 299 shield overrun that you can apply to any item you want.

Click to expand...

This isn't true, because there's an overflow correction that applies to the yield from chopping, just as to production in general. Look at the hammers you get from chopping when you have a bonus and have enough to complete the project, and you'll see that it's less than the formulas above.

It can be abused, but not to the extent that you state. And "overflow correction" can also work against you, most notably when the next project is something on which you would also have had a bonus.

Ok you're right - there's a 50% "overflow correction tax".

So in my example you have a 239-shield overrun for chopping 4*30 forest shields.

DaveMcW said:

Ok you're right - there's a 50% "overflow correction tax".

Click to expand...

I haven't checked it myself, but that could be right.

It's disappointing that they made such a botch of "overflow correction". It seems that they really tried to do the right thing, but just didn't ask the right people how to do it. It would have been no more work to just do it right.

The really frustrating situation is the reverse: when you have an overflow to a project with a large bonus, and you effectively lose most of the credit you should get.

In relation to overflow:
It's maximum seems to me to be limited to the amount the current item is worth. I.e. producing a warrior for 15 shields and chopping for 45 will result in a maximum overflow of 15.

In relation to the forest chopping grid:
The main point of this graph (i.m.o.) is that you can chop pretty effective outside of your fat cross and still get very decent returns. I am already in the habit of chopping the 45 and 37 tiles outside of my fat cross first (assuming it's safe, which is in the HOF: Always )

Regarding overflow, I explained everything here.
(btw including chopping details; although without nice graphics. I thought it would be clear without)

Grids are much prettier than formulas.

karmina said:

Regarding overflow, I explained everything here.
(btw including chopping details; although without nice graphics. I thought it would be clear without)

Click to expand...

Well, I'm not sure what to believe, not having checked any of this myself.

E.g., suppose I already have enough production on a wonder to finish it. I have +150% for that wonder from resource and industrious trait (i.e., s=1.5) and no general production bonus (i.e., g=0). I chop another forest that would normally send 30 hammers to that city. As I understand your formulas:

BP = 30 for the chop
NP = 0
P = 30*2.5 = 75
TO = 75
C = min(75*1.5/2.5, 30*1.5^2/2.5) = min(45, 27) = 27
O = 75-27 = 48.

On the other hand, DaveMcW (if I understand his post #10 correctly) claims to observe O=60 in this case.

I could set up a test myself. It does seem pretty clear that you can get more carryover than you should. It also seems that timing chops for the last turn when you're finishing a project with a high bonus, is going to be sometimes worthwhile.

It's certainly frustrating that they evidently went to some lengths to handle carryover in order to reduce micromanagement, but, they didn't ask the right people how to do it correctly.

DaviddesJ said:

C = min(75*1.5/2.5, 30*1.5^2/2.5) = min(45, 27) = 27
O = 75-27 = 48.
On the other hand, DaveMcW (if I understand his post #10 correctly) claims to observe O=60 in this case.

Click to expand...

Admittedly I didn't test the special case of chopping overflow in detail, but I think that the base production in the formula should be the city's BP, not the 30 chop BP. So when maximizing overflow, it also depends on the city and tiles worked.

It's certainly frustrating that they evidently went to some lengths to handle carryover in order to reduce micromanagement, but, they didn't ask the right people how to do it correctly.

Click to expand...

I don't see what "right people" they needed to "ask". It's pretty obvious how it should work: simply in the one and only fair way, which means that exactly the shields needed for a special bonus project get the bonus multipliers, and that no shields are lost. Everyone agrees about that.
The only issue where community opinions vary is whether to grant overflow production any special bonus multiplier of the next project.
And as I pointed out, Firaxis probably wanted to do it the right way, but unfortunately made a slight mistake in the formula and failed to fix it up to now.

karmina said:

And as I pointed out, Firaxis probably wanted to do it the right way, but unfortunately made a slight mistake in the formula and failed to fix it up to now.

Click to expand...

Well the 'right people' in this case would be someone with
1) basic mathematical knowledge
2) knowledge of how the bonuses worked
3) knowledge of what they wanted the overflow to do
4) an ability to catch bugs in the code

The fact is Firaxis failed miserably on having the people in their organization that had all those skills/traits talking to each other well enough. Meaning that the overflow situation is either a programming bug (correct formula was known but not put in properly) or a design formula bug (correct effect was known but an improper formula was used).

karmina said:

Admittedly I didn't test the special case of chopping overflow in detail, but I think that the base production in the formula should be the city's BP, not the 30 chop BP. So when maximizing overflow, it also depends on the city and tiles worked.

Click to expand...

I don't really understand this statement. When you chop a forest that generates more shields than the current project requires, the "overflow correction" is generated immediately as you chop. E.g., you chop a forest that would normally yield 75 hammers to a wonder with +150%, but it actually gives a smaller number.

It wouldn't make any sense at all to me if the amount of "overflow correction" applied to the forest chop depends on the base production of the city. This would mean, among other things, that going into the city, turning all of its citizens into specialists, completing the chop, and then changing them back, would allow you to affect the result that you get. That certainly wouldn't be good, and I hope it's not the case.

If you haven't tested it at all, then someone will have to do some tests to figure out how it does work.

karmina said:

I don't see what "right people" they needed to "ask". It's pretty obvious how it should work: simply in the one and only fair way, which means that exactly the shields needed for a special bonus project get the bonus multipliers, and that no shields are lost. Everyone agrees about that.
The only issue where community opinions vary is whether to grant overflow production any special bonus multiplier of the next project.
And as I pointed out, Firaxis probably wanted to do it the right way, but unfortunately made a slight mistake in the formula and failed to fix it up to now.

Click to expand...

If it were so obvious how it should work, then they would have gotten it right. But there are many things that are obvious to me yet won't be obvious to someone who's never taken a single math class past high school.

And the biggest problem with the current system is not how the "overflow correction" is computed, but the fact that the subsequent project doesn't get any bonus multipliers. So, e.g., if you have a city that's building Knights, and it has Heroic Epic for +100%, then you get 1 Knight every two turns if you can get to 45 hammers/turn with the bonus, but if you only can get 44 hammers/turn then you do much worse, because each time you finish a Knight you lose several hammers to "overflow correction". This defeats the whole point of the new system which is supposed to let players not have to micromanage exactly how much production they generate. There's not really a matter of opinion here: there's one right way to do it.

Just wanted to bump this up as I needed to use it and had to scroll through 3 pages to find it... would be cool if this chop grid could be included in the Civ4 Reference Charts. Great tool by the way Ozzy