Wood or Lumber is one of the most important items in any Harvest Moon or Rune Factory game, as it is required for the many construction and upgrade projects that will contribute to your Character's success. You need Lumber for Animal Barns, house upgrades and in some games, for Maker Sheds and other buildings. Without an upgrade or sometimes two to your House, you often will be unable to marry.
In many Harvest Moon games, you can purchase Wood/Lumber from a local merchant as well as chopping branches and stumps to create it. The price may be high, but as long as the option exists, you always can sacrifice luxuries and other purchase options in order to buy the Lumber you need for the project dearest to your heart.
In Rune Factory, however, you cannot purchase Wood/Lumber from any one. With your original Axe, you will not be able to chop Stumps for Lumber either. This limits you to the branches that appear on your Field and untilled Fields in every Cave/Dungeon.
A question that many players ask, therefore, is how to obtain MORE lumber for the upgrades they desperately need. There are two solutions.
The first is by using your Fishing Rod. Branches are one of the items that you will 'catch' when Fishing in most Harvest Moon/Rune Factory games. In most games, however, they are little more than a nuisance. In Rune Factory, on the other hand, they are more than worth their weight in gold. Any 'branch' you obtain with a Fishing Rod can be thrown down onto your Field and chopped into Wood/Lumber. Fishing therefore can be a better source of Lumber than you may have imagined...
Note that branches are more plentiful in some locations than others. A location that is poor in terms of catching fish will be a treasure trove for Branches (and other rubbish items!)
The second method of obtaining Wood/Lumber is through trade. This is extremely tedious and requires another DS, but Wood/Lumber can be traded. Unfortunately, you cannot trade 'stacks' of any item in Rune Factory. You must place a single piece of Wood/Lumber in every slot and then make the trade. The recipient must have an empty slot in his/her rucksack for EACH. Items received in trade do not stack upon arrival. Unless you have an empty slot for each item, the trade will fail completely.
Incidentally, there is quite a big difference between the original Rune Factory and Rune Factory 2 in terms of Lumber/Wood and the difference probably stems from the difficulty players experienced in the original. In Rune Factory 2, many of the rewards for completing Requests on the Bulletin Board include 100 Wood/Lumber. This means that, if you steadily increase Friendship levels with all Characters and perform all Requests, you never should be at a loss for the lumber needed for every building projest or upgrade. In the original Rune Factory, you do not have an opportunity to obtain gifts of 100 Wood/Lumber from the residents of Kardia in any comparable fashion.
The original Rune Factory spans only a single generation and there is no reason why you should be in a hurry to complete the game. As long as you can obtain 100 Wood for the first Monster Barn, you will be in good shape to begin exploring Dungeons and increasing your levels so that you can unlock new dungeons. As Rune Factory 2 spans two generations, the initial gifts of 100 Wood/Lumber from other characters probably were intended to motivate players who might otherwise have been discouraged by difficulties achieving initial goals in the 1st Generation.
Moving forward too quickly in any Harvest Moon/Rune Factory game carries its own disadvantages. One could argue that your character needs Lumber quickly for the house expansion in the original Rune Factory, but the Small Kitchen actually is sufficient at the beginning of the first year. In Rune Factory, having a Recipe and the proper utensils to make a Dish is not sufficient to guarantee success. You must practice simple Recipes again and again in order to increase your cooking skills to the point where you will succeed at more difficult or complex Recipes.
In all three Rune Factory games that I have covered, players often ask me how to defeat a specific Boss, after having been defeated again and again when they have attempted battle. Usually, the real reason for the defeat is because their Experience Levels are too low. I may err on the side of caution, but when I go into battle, I usually have more than sufficient experience and skill to defeat my opponent. I always look for a Wolf for Transport in any Rune Factory game, but in Rune Factory Frontier, you will not be able to tame a Monster until your Skill Levels are within the required Levels for that specific Monster type. This means, effectively, that you must raise your levels a little before you venture onto the Whale's Fin to tame your first Silver Wolf. Everything in its own time...